diff --git a/test/run/idl-ops.mo b/test/run/idl-ops.mo
index bd91492229f..15a2746cdbd 100644
--- a/test/run/idl-ops.mo
+++ b/test/run/idl-ops.mo
@@ -49,10 +49,9 @@ assert((?arrayNat) == deserArrayInt (serArrayInt arrayNat));
 assert((?arrayNat) == deserArrayInt (serArrayInt arrayNat));
 assert(null == deserArrayNat (serArrayInt arrayInt));
 assert((?arrayInt) == deserArrayInt (serArrayInt arrayInt));
-
 let heapDifference = Prim.rts_heap_size() : Int - started_with;
 // Difference between incremental and non-incremental GC
-assert(heapDifference == +12_672 or heapDifference == +13_288);
+assert(heapDifference == +6_848 or heapDifference == +7_464);
 
 //SKIP run
 //SKIP run-ir
diff --git a/test/run/idl.mo b/test/run/idl.mo
index 6122d2a235b..3ab349baf66 100644
--- a/test/run/idl.mo
+++ b/test/run/idl.mo
@@ -47,7 +47,7 @@ assert(arrayInt == deserArrayInt (serArrayInt arrayInt));
 
 let heapDifference = Prim.rts_heap_size() : Int - started_with;
 // Difference between incremental and non-incremental GC
-assert(heapDifference == +8_744 or heapDifference == +9_144);
+assert(heapDifference == +4_488 or heapDifference == +4_888);
 
 //SKIP run
 //SKIP run-ir