diff --git a/core/compiler/constants/constants.factor b/core/compiler/constants/constants.factor
index 9594cf7b23..8610f490ec 100755
--- a/core/compiler/constants/constants.factor
+++ b/core/compiler/constants/constants.factor
@@ -4,8 +4,8 @@ USING: math kernel layouts system ;
 IN: compiler.constants
 
 ! These constants must match vm/memory.h
-: card-bits 6 ;
-: deck-bits 12 ;
+: card-bits 8 ;
+: deck-bits 18 ;
 : card-mark HEX: 40 HEX: 80 bitor ;
 
 ! These constants must match vm/layouts.h
diff --git a/vm/data_gc.h b/vm/data_gc.h
index 30a4aee6ee..3c21695c2c 100755
--- a/vm/data_gc.h
+++ b/vm/data_gc.h
@@ -70,7 +70,7 @@ the offset of the first object is set by the allocator. */
 #define CARD_MARK_MASK (CARD_POINTS_TO_NURSERY | CARD_POINTS_TO_AGING)
 typedef u8 F_CARD;
 
-#define CARD_BITS 6
+#define CARD_BITS 8
 #define CARD_SIZE (1<<CARD_BITS)
 #define ADDR_CARD_MASK (CARD_SIZE-1)
 
@@ -81,7 +81,7 @@ DLLEXPORT CELL cards_offset;
 
 typedef u8 F_DECK;
 
-#define DECK_BITS (CARD_BITS + 6)
+#define DECK_BITS (CARD_BITS + 10)
 #define DECK_SIZE (1<<DECK_BITS)
 #define ADDR_DECK_MASK (DECK_SIZE-1)