diff --git a/ext/json/ext/parser/parser.c b/ext/json/ext/parser/parser.c
index 09ca4f75a..baac2b554 100644
--- a/ext/json/ext/parser/parser.c
+++ b/ext/json/ext/parser/parser.c
@@ -460,10 +460,12 @@ enum {JSON_object_error = 0};
 enum {JSON_object_en_main = 1};
 
 
-#line 514 "parser.rl"
+#line 527 "parser.rl"
 
 
 #define PUSH(result) rvalue_stack_push(json->stack, result, &json->stack_handle, &json->stack)
+#define PEEK(count) rvalue_stack_peek(json->stack, count)
+#define POP(count) rvalue_stack_pop(json->stack, count)
 
 static char *JSON_parse_object(JSON_Parser *json, char *p, char *pe, VALUE *result, int current_nesting)
 {
@@ -473,17 +475,23 @@ static char *JSON_parse_object(JSON_Parser *json, char *p, char *pe, VALUE *resu
         rb_raise(eNestingError, "nesting of %d is too deep", current_nesting);
     }
 
+    VALUE cache[20];
+    unsigned int cache_count = 0;
+    // speculate we are parsing a hash
+    VALUE hash = 0;
+    VALUE key = Qnil;
+
     long stack_head = json->stack->head;
 
 
-#line 480 "parser.c"
+#line 488 "parser.c"
 	{
 	cs = JSON_object_start;
 	}
 
-#line 529 "parser.rl"
+#line 550 "parser.rl"
 
-#line 487 "parser.c"
+#line 495 "parser.c"
 	{
 	short _widec;
 	if ( p == pe )
@@ -512,14 +520,14 @@ case 2:
 		goto st2;
 	goto st0;
 tr2:
-#line 493 "parser.rl"
+#line 506 "parser.rl"
 	{
         char *np;
         json->parsing_name = true;
-        np = JSON_parse_string(json, p, pe, result);
+        np = JSON_parse_string(json, p, pe, &cache[cache_count]);
+        cache_count++;
         json->parsing_name = false;
         if (np == NULL) { p--; {p++; cs = 3; goto _out;} } else {
-            PUSH(*result);
             {p = (( np))-1;}
          }
     }
@@ -528,7 +536,7 @@ case 2:
 	if ( ++p == pe )
 		goto _test_eof3;
 case 3:
-#line 532 "parser.c"
+#line 540 "parser.c"
 	switch( (*p) ) {
 		case 13: goto st3;
 		case 32: goto st3;
@@ -597,10 +605,23 @@ case 8:
 tr11:
 #line 482 "parser.rl"
 	{
-        char *np = JSON_parse_value(json, p, pe, result, current_nesting);
+        VALUE val;
+        char *np = JSON_parse_value(json, p, pe, &cache[cache_count], current_nesting);
         if (np == NULL) {
             p--; {p++; cs = 9; goto _out;}
         } else {
+            cache_count++;
+            if (cache_count == 20) {
+                if (!hash) {
+#ifdef HAVE_RB_HASH_NEW_CAPA
+                    hash = rb_hash_new_capa(20);
+#else
+                    hash = rb_hash_new();
+#endif
+                }
+                rb_hash_bulk_insert(20, cache, hash);
+                cache_count = 0;
+            }
             {p = (( np))-1;}
         }
     }
@@ -609,20 +630,20 @@ case 8:
 	if ( ++p == pe )
 		goto _test_eof9;
 case 9:
-#line 613 "parser.c"
+#line 634 "parser.c"
 	_widec = (*p);
 	if ( (*p) < 13 ) {
 		if ( (*p) > 9 ) {
 			if ( 10 <= (*p) && (*p) <= 10 ) {
 				_widec = (short)(128 + ((*p) - -128));
 				if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 			}
 		} else if ( (*p) >= 9 ) {
 			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else if ( (*p) > 13 ) {
@@ -630,26 +651,26 @@ case 9:
 			if ( 32 <= (*p) && (*p) <= 32 ) {
 				_widec = (short)(128 + ((*p) - -128));
 				if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 			}
 		} else if ( (*p) > 44 ) {
 			if ( 47 <= (*p) && (*p) <= 47 ) {
 				_widec = (short)(128 + ((*p) - -128));
 				if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 			}
 		} else {
 			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else {
 		_widec = (short)(128 + ((*p) - -128));
 		if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 	}
 	switch( _widec ) {
@@ -670,14 +691,14 @@ case 9:
 		goto st10;
 	goto st0;
 tr4:
-#line 504 "parser.rl"
+#line 517 "parser.rl"
 	{ p--; {p++; cs = 32; goto _out;} }
 	goto st32;
 st32:
 	if ( ++p == pe )
 		goto _test_eof32;
 case 32:
-#line 681 "parser.c"
+#line 702 "parser.c"
 	goto st0;
 st10:
 	if ( ++p == pe )
@@ -779,13 +800,13 @@ case 20:
 		if ( 47 <= (*p) && (*p) <= 47 ) {
 			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else if ( (*p) >= 42 ) {
 		_widec = (short)(128 + ((*p) - -128));
 		if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 	}
 	switch( _widec ) {
@@ -804,20 +825,20 @@ case 21:
 		if ( (*p) <= 41 ) {
 			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else if ( (*p) > 42 ) {
 		if ( 43 <= (*p) )
  {			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else {
 		_widec = (short)(128 + ((*p) - -128));
 		if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 	}
 	switch( _widec ) {
@@ -840,13 +861,13 @@ case 22:
 			if ( 42 <= (*p) && (*p) <= 42 ) {
 				_widec = (short)(128 + ((*p) - -128));
 				if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 			}
 		} else {
 			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else if ( (*p) > 46 ) {
@@ -854,19 +875,19 @@ case 22:
 			if ( 48 <= (*p) )
  {				_widec = (short)(128 + ((*p) - -128));
 				if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 			}
 		} else if ( (*p) >= 47 ) {
 			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else {
 		_widec = (short)(128 + ((*p) - -128));
 		if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 	}
 	switch( _widec ) {
@@ -890,20 +911,20 @@ case 23:
 		if ( (*p) <= 9 ) {
 			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else if ( (*p) > 10 ) {
 		if ( 11 <= (*p) )
  {			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else {
 		_widec = (short)(128 + ((*p) - -128));
 		if (
-#line 491 "parser.rl"
+#line 504 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 	}
 	switch( _widec ) {
@@ -1017,32 +1038,31 @@ case 31:
 	_out: {}
 	}
 
-#line 530 "parser.rl"
+#line 551 "parser.rl"
 
     if (cs >= JSON_object_first_final) {
         long count = json->stack->head - stack_head;
 
-        if (RB_UNLIKELY(json->object_class)) {
-            VALUE object = rb_class_new_instance(0, 0, json->object_class);
-            long index = 0;
-            VALUE *items = rvalue_stack_peek(json->stack, count);
-            while (index < count) {
-                VALUE name = items[index++];
-                VALUE value = items[index++];
-                rb_funcall(object, i_aset, 2, name, value);
-            }
-            *result = object;
-        } else {
-            VALUE hash;
+        if (!hash) {
 #ifdef HAVE_RB_HASH_NEW_CAPA
-            hash = rb_hash_new_capa(count >> 1);
+            hash = rb_hash_new_capa(cache_count);
 #else
             hash = rb_hash_new();
 #endif
-            rb_hash_bulk_insert(count, rvalue_stack_peek(json->stack, count), hash);
+        }
+
+        if (cache_count > 0) {
+            rb_hash_bulk_insert(cache_count, cache, hash);
+            cache_count = 0;
+        }
+
+        if (RB_UNLIKELY(json->object_class)) {
+            VALUE object = rb_class_new_instance(0, 0, json->object_class);
+            rb_funcall(cParser, rb_intern("convert_hash"), 2, hash, object);
+            *result = object;
+        } else {
             *result = hash;
         }
-        rvalue_stack_pop(json->stack, count);
 
         if (RB_UNLIKELY(json->create_additions)) {
             VALUE klassname;
@@ -1068,7 +1088,7 @@ case 31:
 }
 
 
-#line 1072 "parser.c"
+#line 1092 "parser.c"
 enum {JSON_value_start = 1};
 enum {JSON_value_first_final = 29};
 enum {JSON_value_error = 0};
@@ -1076,7 +1096,7 @@ enum {JSON_value_error = 0};
 enum {JSON_value_en_main = 1};
 
 
-#line 661 "parser.rl"
+#line 681 "parser.rl"
 
 
 static char *JSON_parse_value(JSON_Parser *json, char *p, char *pe, VALUE *result, int current_nesting)
@@ -1084,14 +1104,14 @@ static char *JSON_parse_value(JSON_Parser *json, char *p, char *pe, VALUE *resul
     int cs = EVIL;
 
 
-#line 1088 "parser.c"
+#line 1108 "parser.c"
 	{
 	cs = JSON_value_start;
 	}
 
-#line 668 "parser.rl"
+#line 688 "parser.rl"
 
-#line 1095 "parser.c"
+#line 1115 "parser.c"
 	{
 	if ( p == pe )
 		goto _test_eof;
@@ -1125,7 +1145,7 @@ case 1:
 cs = 0;
 	goto _out;
 tr2:
-#line 608 "parser.rl"
+#line 628 "parser.rl"
 	{
         char *np = JSON_parse_string(json, p, pe, result);
         if (np == NULL) {
@@ -1137,7 +1157,7 @@ cs = 0;
     }
 	goto st29;
 tr3:
-#line 618 "parser.rl"
+#line 638 "parser.rl"
 	{
         char *np;
         if(pe > p + 8 && !strncmp(MinusInfinity, p, 9)) {
@@ -1157,7 +1177,7 @@ cs = 0;
     }
 	goto st29;
 tr7:
-#line 636 "parser.rl"
+#line 656 "parser.rl"
 	{
         char *np;
         np = JSON_parse_array(json, p, pe, result, current_nesting + 1);
@@ -1165,7 +1185,7 @@ cs = 0;
     }
 	goto st29;
 tr11:
-#line 642 "parser.rl"
+#line 662 "parser.rl"
 	{
         char *np;
         np =  JSON_parse_object(json, p, pe, result, current_nesting + 1);
@@ -1173,7 +1193,7 @@ cs = 0;
     }
 	goto st29;
 tr25:
-#line 601 "parser.rl"
+#line 621 "parser.rl"
 	{
         if (json->allow_nan) {
             *result = CInfinity;
@@ -1183,7 +1203,7 @@ cs = 0;
     }
 	goto st29;
 tr27:
-#line 594 "parser.rl"
+#line 614 "parser.rl"
 	{
         if (json->allow_nan) {
             *result = CNaN;
@@ -1193,19 +1213,19 @@ cs = 0;
     }
 	goto st29;
 tr31:
-#line 588 "parser.rl"
+#line 608 "parser.rl"
 	{
         *result = Qfalse;
     }
 	goto st29;
 tr34:
-#line 585 "parser.rl"
+#line 605 "parser.rl"
 	{
         *result = Qnil;
     }
 	goto st29;
 tr37:
-#line 591 "parser.rl"
+#line 611 "parser.rl"
 	{
         *result = Qtrue;
     }
@@ -1214,9 +1234,9 @@ cs = 0;
 	if ( ++p == pe )
 		goto _test_eof29;
 case 29:
-#line 648 "parser.rl"
+#line 668 "parser.rl"
 	{ p--; {p++; cs = 29; goto _out;} }
-#line 1220 "parser.c"
+#line 1240 "parser.c"
 	switch( (*p) ) {
 		case 13: goto st29;
 		case 32: goto st29;
@@ -1457,14 +1477,13 @@ case 28:
 	_out: {}
 	}
 
-#line 669 "parser.rl"
+#line 689 "parser.rl"
 
     if (json->freeze) {
         OBJ_FREEZE(*result);
     }
 
     if (cs >= JSON_value_first_final) {
-        PUSH(*result);
         return p;
     } else {
         return NULL;
@@ -1472,7 +1491,7 @@ case 28:
 }
 
 
-#line 1476 "parser.c"
+#line 1495 "parser.c"
 enum {JSON_integer_start = 1};
 enum {JSON_integer_first_final = 3};
 enum {JSON_integer_error = 0};
@@ -1480,7 +1499,7 @@ enum {JSON_integer_error = 0};
 enum {JSON_integer_en_main = 1};
 
 
-#line 690 "parser.rl"
+#line 709 "parser.rl"
 
 
 #define MAX_FAST_INTEGER_SIZE 18
@@ -1520,7 +1539,7 @@ static char *JSON_decode_integer(JSON_Parser *json, char *p, VALUE *result)
 }
 
 
-#line 1524 "parser.c"
+#line 1543 "parser.c"
 enum {JSON_float_start = 1};
 enum {JSON_float_first_final = 6};
 enum {JSON_float_error = 0};
@@ -1528,7 +1547,7 @@ enum {JSON_float_error = 0};
 enum {JSON_float_en_main = 1};
 
 
-#line 742 "parser.rl"
+#line 761 "parser.rl"
 
 
 static char *JSON_parse_number(JSON_Parser *json, char *p, char *pe, VALUE *result)
@@ -1537,15 +1556,15 @@ static char *JSON_parse_number(JSON_Parser *json, char *p, char *pe, VALUE *resu
     bool is_float = false;
 
 
-#line 1541 "parser.c"
+#line 1560 "parser.c"
 	{
 	cs = JSON_float_start;
 	}
 
-#line 750 "parser.rl"
+#line 769 "parser.rl"
     json->memo = p;
 
-#line 1549 "parser.c"
+#line 1568 "parser.c"
 	{
 	if ( p == pe )
 		goto _test_eof;
@@ -1585,24 +1604,24 @@ case 6:
 		goto st0;
 	goto tr7;
 tr7:
-#line 734 "parser.rl"
+#line 753 "parser.rl"
 	{ p--; {p++; cs = 7; goto _out;} }
 	goto st7;
 st7:
 	if ( ++p == pe )
 		goto _test_eof7;
 case 7:
-#line 1596 "parser.c"
+#line 1615 "parser.c"
 	goto st0;
 tr8:
-#line 735 "parser.rl"
+#line 754 "parser.rl"
 	{  is_float = true; }
 	goto st3;
 st3:
 	if ( ++p == pe )
 		goto _test_eof3;
 case 3:
-#line 1606 "parser.c"
+#line 1625 "parser.c"
 	if ( 48 <= (*p) && (*p) <= 57 )
 		goto st8;
 	goto st0;
@@ -1621,14 +1640,14 @@ case 8:
 		goto st0;
 	goto tr7;
 tr9:
-#line 735 "parser.rl"
+#line 754 "parser.rl"
 	{  is_float = true; }
 	goto st4;
 st4:
 	if ( ++p == pe )
 		goto _test_eof4;
 case 4:
-#line 1632 "parser.c"
+#line 1651 "parser.c"
 	switch( (*p) ) {
 		case 43: goto st5;
 		case 45: goto st5;
@@ -1685,7 +1704,7 @@ case 10:
 	_out: {}
 	}
 
-#line 752 "parser.rl"
+#line 771 "parser.rl"
 
     if (cs >= JSON_float_first_final) {
         if (!is_float) {
@@ -1741,7 +1760,7 @@ case 10:
 
 
 
-#line 1745 "parser.c"
+#line 1764 "parser.c"
 enum {JSON_array_start = 1};
 enum {JSON_array_first_final = 22};
 enum {JSON_array_error = 0};
@@ -1749,7 +1768,7 @@ enum {JSON_array_error = 0};
 enum {JSON_array_en_main = 1};
 
 
-#line 832 "parser.rl"
+#line 861 "parser.rl"
 
 
 static char *JSON_parse_array(JSON_Parser *json, char *p, char *pe, VALUE *result, int current_nesting)
@@ -1759,17 +1778,21 @@ static char *JSON_parse_array(JSON_Parser *json, char *p, char *pe, VALUE *resul
     if (json->max_nesting && current_nesting > json->max_nesting) {
         rb_raise(eNestingError, "nesting of %d is too deep", current_nesting);
     }
-    long stack_head = json->stack->head;
+
+    // speculate that it's a regular array
+    VALUE cache[20];
+    unsigned int cache_count = 0;
+    VALUE ary = 0;
 
 
-#line 1766 "parser.c"
+#line 1789 "parser.c"
 	{
 	cs = JSON_array_start;
 	}
 
-#line 844 "parser.rl"
+#line 877 "parser.rl"
 
-#line 1773 "parser.c"
+#line 1796 "parser.c"
 	{
 	short _widec;
 	if ( p == pe )
@@ -1809,13 +1832,23 @@ case 2:
 		goto st2;
 	goto st0;
 tr2:
-#line 812 "parser.rl"
+#line 831 "parser.rl"
 	{
-        VALUE v = Qnil;
-        char *np = JSON_parse_value(json, p, pe, &v, current_nesting);
+        char *np = JSON_parse_value(json, p, pe, &cache[cache_count], current_nesting);
         if (np == NULL) {
             p--; {p++; cs = 3; goto _out;}
         } else {
+            cache_count++;
+            if (cache_count == 20) {
+                if (!ary) {
+                    ary = rb_ary_new_from_values(cache_count, cache);
+                    cache_count = 0;
+                }
+                else {
+                    rb_ary_concat(ary, rb_ary_new_from_values(cache_count, cache));
+                    cache_count = 0;
+                }
+            }
             {p = (( np))-1;}
         }
     }
@@ -1824,12 +1857,12 @@ case 2:
 	if ( ++p == pe )
 		goto _test_eof3;
 case 3:
-#line 1828 "parser.c"
+#line 1861 "parser.c"
 	_widec = (*p);
 	if ( 44 <= (*p) && (*p) <= 44 ) {
 		_widec = (short)(128 + ((*p) - -128));
 		if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 	}
 	switch( _widec ) {
@@ -1876,14 +1909,14 @@ case 7:
 		goto st3;
 	goto st7;
 tr4:
-#line 824 "parser.rl"
+#line 853 "parser.rl"
 	{ p--; {p++; cs = 22; goto _out;} }
 	goto st22;
 st22:
 	if ( ++p == pe )
 		goto _test_eof22;
 case 22:
-#line 1887 "parser.c"
+#line 1920 "parser.c"
 	goto st0;
 st8:
 	if ( ++p == pe )
@@ -1951,13 +1984,13 @@ case 13:
 			if ( 10 <= (*p) && (*p) <= 10 ) {
 				_widec = (short)(128 + ((*p) - -128));
 				if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 			}
 		} else if ( (*p) >= 9 ) {
 			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else if ( (*p) > 13 ) {
@@ -1965,19 +1998,19 @@ case 13:
 			if ( 47 <= (*p) && (*p) <= 47 ) {
 				_widec = (short)(128 + ((*p) - -128));
 				if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 			}
 		} else if ( (*p) >= 32 ) {
 			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else {
 		_widec = (short)(128 + ((*p) - -128));
 		if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 	}
 	switch( _widec ) {
@@ -2016,13 +2049,13 @@ case 14:
 		if ( 47 <= (*p) && (*p) <= 47 ) {
 			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else if ( (*p) >= 42 ) {
 		_widec = (short)(128 + ((*p) - -128));
 		if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 	}
 	switch( _widec ) {
@@ -2041,20 +2074,20 @@ case 15:
 		if ( (*p) <= 41 ) {
 			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else if ( (*p) > 42 ) {
 		if ( 43 <= (*p) )
  {			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else {
 		_widec = (short)(128 + ((*p) - -128));
 		if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 	}
 	switch( _widec ) {
@@ -2077,13 +2110,13 @@ case 16:
 			if ( 42 <= (*p) && (*p) <= 42 ) {
 				_widec = (short)(128 + ((*p) - -128));
 				if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 			}
 		} else {
 			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else if ( (*p) > 46 ) {
@@ -2091,19 +2124,19 @@ case 16:
 			if ( 48 <= (*p) )
  {				_widec = (short)(128 + ((*p) - -128));
 				if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 			}
 		} else if ( (*p) >= 47 ) {
 			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else {
 		_widec = (short)(128 + ((*p) - -128));
 		if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 	}
 	switch( _widec ) {
@@ -2127,20 +2160,20 @@ case 17:
 		if ( (*p) <= 9 ) {
 			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else if ( (*p) > 10 ) {
 		if ( 11 <= (*p) )
  {			_widec = (short)(128 + ((*p) - -128));
 			if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 		}
 	} else {
 		_widec = (short)(128 + ((*p) - -128));
 		if (
-#line 822 "parser.rl"
+#line 851 "parser.rl"
  json->allow_trailing_comma  ) _widec += 256;
 	}
 	switch( _widec ) {
@@ -2212,24 +2245,30 @@ case 21:
 	_out: {}
 	}
 
-#line 845 "parser.rl"
+#line 878 "parser.rl"
 
     if(cs >= JSON_array_first_final) {
-        long count = json->stack->head - stack_head;
+        if (!ary) {
+            ary = rb_ary_new_from_values(cache_count, cache);
+            cache_count = 0;
+        }
+        else {
+            if (cache_count > 0) {
+                rb_ary_concat(ary, rb_ary_new_from_values(cache_count, cache));
+                cache_count = 0;
+            }
+        }
 
         if (RB_UNLIKELY(json->array_class)) {
             VALUE array = rb_class_new_instance(0, 0, json->array_class);
-            VALUE *items = rvalue_stack_peek(json->stack, count);
             long index;
-            for (index = 0; index < count; index++) {
-                rb_funcall(array, i_leftshift, 1, items[index]);
+            for (index = 0; index < RARRAY_LEN(ary); index++) {
+                rb_funcall(array, i_leftshift, 1, rb_ary_entry(ary, index));
             }
             *result = array;
         } else {
-            VALUE array = rb_ary_new_from_values(count, rvalue_stack_peek(json->stack, count));
-            *result = array;
+            *result = ary;
         }
-        rvalue_stack_pop(json->stack, count);
 
         return p + 1;
     } else {
@@ -2406,7 +2445,7 @@ static VALUE json_string_unescape(JSON_Parser *json, char *string, char *stringE
 }
 
 
-#line 2410 "parser.c"
+#line 2449 "parser.c"
 enum {JSON_string_start = 1};
 enum {JSON_string_first_final = 9};
 enum {JSON_string_error = 0};
@@ -2414,7 +2453,7 @@ enum {JSON_string_error = 0};
 enum {JSON_string_en_main = 1};
 
 
-#line 1068 "parser.rl"
+#line 1107 "parser.rl"
 
 
 static int
@@ -2435,15 +2474,15 @@ static char *JSON_parse_string(JSON_Parser *json, char *p, char *pe, VALUE *resu
     VALUE match_string;
 
 
-#line 2439 "parser.c"
+#line 2478 "parser.c"
 	{
 	cs = JSON_string_start;
 	}
 
-#line 1088 "parser.rl"
+#line 1127 "parser.rl"
     json->memo = p;
 
-#line 2447 "parser.c"
+#line 2486 "parser.c"
 	{
 	if ( p == pe )
 		goto _test_eof;
@@ -2468,14 +2507,14 @@ case 2:
 		goto st0;
 	goto st2;
 tr2:
-#line 1050 "parser.rl"
+#line 1089 "parser.rl"
 	{
         *result = json_string_fastpath(json, json->memo + 1, p, json->parsing_name, json->parsing_name || json-> freeze, json->parsing_name && json->symbolize_names);
         {p = (( p + 1))-1;}
         p--;
         {p++; cs = 9; goto _out;}
     }
-#line 1043 "parser.rl"
+#line 1082 "parser.rl"
 	{
         *result = json_string_unescape(json, json->memo + 1, p, json->parsing_name, json->parsing_name || json-> freeze, json->parsing_name && json->symbolize_names);
         {p = (( p + 1))-1;}
@@ -2484,7 +2523,7 @@ case 2:
     }
 	goto st9;
 tr6:
-#line 1043 "parser.rl"
+#line 1082 "parser.rl"
 	{
         *result = json_string_unescape(json, json->memo + 1, p, json->parsing_name, json->parsing_name || json-> freeze, json->parsing_name && json->symbolize_names);
         {p = (( p + 1))-1;}
@@ -2496,7 +2535,7 @@ case 2:
 	if ( ++p == pe )
 		goto _test_eof9;
 case 9:
-#line 2500 "parser.c"
+#line 2539 "parser.c"
 	goto st0;
 st3:
 	if ( ++p == pe )
@@ -2584,7 +2623,7 @@ case 8:
 	_out: {}
 	}
 
-#line 1090 "parser.rl"
+#line 1129 "parser.rl"
 
     if (json->create_additions && RTEST(match_string = json->match_string)) {
           VALUE klass;
@@ -2737,7 +2776,7 @@ static VALUE cParser_initialize(int argc, VALUE *argv, VALUE self)
 }
 
 
-#line 2741 "parser.c"
+#line 2780 "parser.c"
 enum {JSON_start = 1};
 enum {JSON_first_final = 10};
 enum {JSON_error = 0};
@@ -2745,7 +2784,7 @@ enum {JSON_error = 0};
 enum {JSON_en_main = 1};
 
 
-#line 1256 "parser.rl"
+#line 1295 "parser.rl"
 
 
 /*
@@ -2762,28 +2801,17 @@ static VALUE cParser_parse(VALUE self)
     VALUE result = Qnil;
     GET_PARSER;
 
-    char stack_buffer[FBUFFER_STACK_SIZE];
-    fbuffer_stack_init(&json->fbuffer, FBUFFER_INITIAL_LENGTH_DEFAULT, stack_buffer, FBUFFER_STACK_SIZE);
-
-    VALUE rvalue_stack_buffer[RVALUE_STACK_INITIAL_CAPA];
-    rvalue_stack stack = {
-        .type = RVALUE_STACK_STACK_ALLOCATED,
-        .ptr = rvalue_stack_buffer,
-        .capa = RVALUE_STACK_INITIAL_CAPA,
-    };
-    json->stack = &stack;
 
-
-#line 2778 "parser.c"
+#line 2806 "parser.c"
 	{
 	cs = JSON_start;
 	}
 
-#line 1284 "parser.rl"
+#line 1312 "parser.rl"
     p = json->source;
     pe = p + json->len;
 
-#line 2787 "parser.c"
+#line 2815 "parser.c"
 	{
 	if ( p == pe )
 		goto _test_eof;
@@ -2817,7 +2845,7 @@ case 1:
 cs = 0;
 	goto _out;
 tr2:
-#line 1248 "parser.rl"
+#line 1287 "parser.rl"
 	{
         char *np = JSON_parse_value(json, p, pe, &result, 0);
         if (np == NULL) { p--; {p++; cs = 10; goto _out;} } else {p = (( np))-1;}
@@ -2827,7 +2855,7 @@ cs = 0;
 	if ( ++p == pe )
 		goto _test_eof10;
 case 10:
-#line 2831 "parser.c"
+#line 2859 "parser.c"
 	switch( (*p) ) {
 		case 13: goto st10;
 		case 32: goto st10;
@@ -2916,7 +2944,7 @@ case 9:
 	_out: {}
 	}
 
-#line 1287 "parser.rl"
+#line 1315 "parser.rl"
 
     if (json->stack_handle) {
         rvalue_stack_eagerly_release(json->stack_handle);
@@ -2943,25 +2971,17 @@ static VALUE cParser_m_parse(VALUE klass, VALUE source, VALUE opts)
     char stack_buffer[FBUFFER_STACK_SIZE];
     fbuffer_stack_init(&json->fbuffer, FBUFFER_INITIAL_LENGTH_DEFAULT, stack_buffer, FBUFFER_STACK_SIZE);
 
-    VALUE rvalue_stack_buffer[RVALUE_STACK_INITIAL_CAPA];
-    rvalue_stack stack = {
-        .type = RVALUE_STACK_STACK_ALLOCATED,
-        .ptr = rvalue_stack_buffer,
-        .capa = RVALUE_STACK_INITIAL_CAPA,
-    };
-    json->stack = &stack;
-
 
-#line 2956 "parser.c"
+#line 2976 "parser.c"
 	{
 	cs = JSON_start;
 	}
 
-#line 1322 "parser.rl"
+#line 1342 "parser.rl"
     p = json->source;
     pe = p + json->len;
 
-#line 2965 "parser.c"
+#line 2985 "parser.c"
 	{
 	if ( p == pe )
 		goto _test_eof;
@@ -2995,7 +3015,7 @@ case 1:
 cs = 0;
 	goto _out;
 tr2:
-#line 1248 "parser.rl"
+#line 1287 "parser.rl"
 	{
         char *np = JSON_parse_value(json, p, pe, &result, 0);
         if (np == NULL) { p--; {p++; cs = 10; goto _out;} } else {p = (( np))-1;}
@@ -3005,7 +3025,7 @@ cs = 0;
 	if ( ++p == pe )
 		goto _test_eof10;
 case 10:
-#line 3009 "parser.c"
+#line 3029 "parser.c"
 	switch( (*p) ) {
 		case 13: goto st10;
 		case 32: goto st10;
@@ -3094,7 +3114,7 @@ case 9:
 	_out: {}
 	}
 
-#line 1325 "parser.rl"
+#line 1345 "parser.rl"
 
     if (json->stack_handle) {
         rvalue_stack_eagerly_release(json->stack_handle);
diff --git a/ext/json/ext/parser/parser.rl b/ext/json/ext/parser/parser.rl
index 9a1f73923..00d13e4c9 100644
--- a/ext/json/ext/parser/parser.rl
+++ b/ext/json/ext/parser/parser.rl
@@ -480,10 +480,23 @@ static void raise_parse_error(const char *format, const char *start)
     write data;
 
     action parse_value {
-        char *np = JSON_parse_value(json, fpc, pe, result, current_nesting);
+        VALUE val;
+        char *np = JSON_parse_value(json, fpc, pe, &cache[cache_count], current_nesting);
         if (np == NULL) {
             fhold; fbreak;
         } else {
+            cache_count++;
+            if (cache_count == 20) {
+                if (!hash) {
+#ifdef HAVE_RB_HASH_NEW_CAPA
+                    hash = rb_hash_new_capa(20);
+#else
+                    hash = rb_hash_new();
+#endif
+                }
+                rb_hash_bulk_insert(20, cache, hash);
+                cache_count = 0;
+            }
             fexec np;
         }
     }
@@ -493,10 +506,10 @@ static void raise_parse_error(const char *format, const char *start)
     action parse_name {
         char *np;
         json->parsing_name = true;
-        np = JSON_parse_string(json, fpc, pe, result);
+        np = JSON_parse_string(json, fpc, pe, &cache[cache_count]);
+        cache_count++;
         json->parsing_name = false;
         if (np == NULL) { fhold; fbreak; } else {
-            PUSH(*result);
             fexec np;
          }
     }
@@ -514,6 +527,8 @@ static void raise_parse_error(const char *format, const char *start)
 }%%
 
 #define PUSH(result) rvalue_stack_push(json->stack, result, &json->stack_handle, &json->stack)
+#define PEEK(count) rvalue_stack_peek(json->stack, count)
+#define POP(count) rvalue_stack_pop(json->stack, count)
 
 static char *JSON_parse_object(JSON_Parser *json, char *p, char *pe, VALUE *result, int current_nesting)
 {
@@ -523,6 +538,12 @@ static char *JSON_parse_object(JSON_Parser *json, char *p, char *pe, VALUE *resu
         rb_raise(eNestingError, "nesting of %d is too deep", current_nesting);
     }
 
+    VALUE cache[20];
+    unsigned int cache_count = 0;
+    // speculate we are parsing a hash
+    VALUE hash = 0;
+    VALUE key = Qnil;
+
     long stack_head = json->stack->head;
 
     %% write init;
@@ -531,27 +552,26 @@ static char *JSON_parse_object(JSON_Parser *json, char *p, char *pe, VALUE *resu
     if (cs >= JSON_object_first_final) {
         long count = json->stack->head - stack_head;
 
-        if (RB_UNLIKELY(json->object_class)) {
-            VALUE object = rb_class_new_instance(0, 0, json->object_class);
-            long index = 0;
-            VALUE *items = rvalue_stack_peek(json->stack, count);
-            while (index < count) {
-                VALUE name = items[index++];
-                VALUE value = items[index++];
-                rb_funcall(object, i_aset, 2, name, value);
-            }
-            *result = object;
-        } else {
-            VALUE hash;
+        if (!hash) {
 #ifdef HAVE_RB_HASH_NEW_CAPA
-            hash = rb_hash_new_capa(count >> 1);
+            hash = rb_hash_new_capa(cache_count);
 #else
             hash = rb_hash_new();
 #endif
-            rb_hash_bulk_insert(count, rvalue_stack_peek(json->stack, count), hash);
+        }
+
+        if (cache_count > 0) {
+            rb_hash_bulk_insert(cache_count, cache, hash);
+            cache_count = 0;
+        }
+
+        if (RB_UNLIKELY(json->object_class)) {
+            VALUE object = rb_class_new_instance(0, 0, json->object_class);
+            rb_funcall(cParser, rb_intern("convert_hash"), 2, hash, object);
+            *result = object;
+        } else {
             *result = hash;
         }
-        rvalue_stack_pop(json->stack, count);
 
         if (RB_UNLIKELY(json->create_additions)) {
             VALUE klassname;
@@ -672,7 +692,6 @@ static char *JSON_parse_value(JSON_Parser *json, char *p, char *pe, VALUE *resul
     }
 
     if (cs >= JSON_value_first_final) {
-        PUSH(*result);
         return p;
     } else {
         return NULL;
@@ -810,11 +829,21 @@ static char *JSON_parse_number(JSON_Parser *json, char *p, char *pe, VALUE *resu
     write data;
 
     action parse_value {
-        VALUE v = Qnil;
-        char *np = JSON_parse_value(json, fpc, pe, &v, current_nesting);
+        char *np = JSON_parse_value(json, fpc, pe, &cache[cache_count], current_nesting);
         if (np == NULL) {
             fhold; fbreak;
         } else {
+            cache_count++;
+            if (cache_count == 20) {
+                if (!ary) {
+                    ary = rb_ary_new_from_values(cache_count, cache);
+                    cache_count = 0;
+                }
+                else {
+                    rb_ary_concat(ary, rb_ary_new_from_values(cache_count, cache));
+                    cache_count = 0;
+                }
+            }
             fexec np;
         }
     }
@@ -838,27 +867,37 @@ static char *JSON_parse_array(JSON_Parser *json, char *p, char *pe, VALUE *resul
     if (json->max_nesting && current_nesting > json->max_nesting) {
         rb_raise(eNestingError, "nesting of %d is too deep", current_nesting);
     }
-    long stack_head = json->stack->head;
+
+    // speculate that it's a regular array
+    VALUE cache[20];
+    unsigned int cache_count = 0;
+    VALUE ary = 0;
 
     %% write init;
     %% write exec;
 
     if(cs >= JSON_array_first_final) {
-        long count = json->stack->head - stack_head;
+        if (!ary) {
+            ary = rb_ary_new_from_values(cache_count, cache);
+            cache_count = 0;
+        }
+        else {
+            if (cache_count > 0) {
+                rb_ary_concat(ary, rb_ary_new_from_values(cache_count, cache));
+                cache_count = 0;
+            }
+        }
 
         if (RB_UNLIKELY(json->array_class)) {
             VALUE array = rb_class_new_instance(0, 0, json->array_class);
-            VALUE *items = rvalue_stack_peek(json->stack, count);
             long index;
-            for (index = 0; index < count; index++) {
-                rb_funcall(array, i_leftshift, 1, items[index]);
+            for (index = 0; index < RARRAY_LEN(ary); index++) {
+                rb_funcall(array, i_leftshift, 1, rb_ary_entry(ary, index));
             }
             *result = array;
         } else {
-            VALUE array = rb_ary_new_from_values(count, rvalue_stack_peek(json->stack, count));
-            *result = array;
+            *result = ary;
         }
-        rvalue_stack_pop(json->stack, count);
 
         return p + 1;
     } else {
@@ -1269,17 +1308,6 @@ static VALUE cParser_parse(VALUE self)
     VALUE result = Qnil;
     GET_PARSER;
 
-    char stack_buffer[FBUFFER_STACK_SIZE];
-    fbuffer_stack_init(&json->fbuffer, FBUFFER_INITIAL_LENGTH_DEFAULT, stack_buffer, FBUFFER_STACK_SIZE);
-
-    VALUE rvalue_stack_buffer[RVALUE_STACK_INITIAL_CAPA];
-    rvalue_stack stack = {
-        .type = RVALUE_STACK_STACK_ALLOCATED,
-        .ptr = rvalue_stack_buffer,
-        .capa = RVALUE_STACK_INITIAL_CAPA,
-    };
-    json->stack = &stack;
-
     %% write init;
     p = json->source;
     pe = p + json->len;
@@ -1310,14 +1338,6 @@ static VALUE cParser_m_parse(VALUE klass, VALUE source, VALUE opts)
     char stack_buffer[FBUFFER_STACK_SIZE];
     fbuffer_stack_init(&json->fbuffer, FBUFFER_INITIAL_LENGTH_DEFAULT, stack_buffer, FBUFFER_STACK_SIZE);
 
-    VALUE rvalue_stack_buffer[RVALUE_STACK_INITIAL_CAPA];
-    rvalue_stack stack = {
-        .type = RVALUE_STACK_STACK_ALLOCATED,
-        .ptr = rvalue_stack_buffer,
-        .capa = RVALUE_STACK_INITIAL_CAPA,
-    };
-    json->stack = &stack;
-
     %% write init;
     p = json->source;
     pe = p + json->len;
diff --git a/lib/json.rb b/lib/json.rb
index dfd9b7dfc..7dabfa928 100644
--- a/lib/json.rb
+++ b/lib/json.rb
@@ -584,4 +584,12 @@
 module JSON
   require 'json/version'
   require 'json/ext'
+
+  class Parser
+    def self.convert_hash(from, to) # :nodoc:
+      from.each_pair { |k,v| to[k] = v }
+      to
+    end
+    private_class_method :convert_hash
+  end
 end