diff --git a/components/multithreadprocs/mtpcpu.pas b/components/multithreadprocs/mtpcpu.pas
index c2f7ddfd5..ee46b7399 100644
--- a/components/multithreadprocs/mtpcpu.pas
+++ b/components/multithreadprocs/mtpcpu.pas
@@ -46,7 +46,7 @@ function GetSystemThreadCount: integer;
 //returns total number of processors available to system including logical hyperthreaded processors
 var
   i: Integer;
-  ProcessAffinityMask, SystemAffinityMask: DWORD;
+  ProcessAffinityMask, SystemAffinityMask: DWORD_PTR;
   Mask: DWORD;
   SystemInfo: SYSTEM_INFO;
 begin