diff --git a/lib/system/gc_ms.nim b/lib/system/gc_ms.nim
index 96221b175b..13a56e8327 100644
--- a/lib/system/gc_ms.nim
+++ b/lib/system/gc_ms.nim
@@ -497,8 +497,9 @@ proc collectCTBody(gch: var GcHeap) =
   sysAssert(allocInv(gch.region), "collectCT: end")
 
 proc collectCT(gch: var GcHeap; size: int) =
+  let fmem = getFreeMem(gch.region)
   if (getOccupiedMem(gch.region) >= gch.cycleThreshold or
-      size > getFreeMem(gch.region)) and gch.recGcLock == 0:
+      size > fmem and fmem > InitialThreshold) and gch.recGcLock == 0:
     collectCTBody(gch)
 
 when not defined(useNimRtl):