diff --git a/libc/nt/version.h b/libc/nt/version.h
index 106cc54eb..1c92f0a7c 100644
--- a/libc/nt/version.h
+++ b/libc/nt/version.h
@@ -9,6 +9,8 @@ bool32 GetVersionEx(struct NtOsVersionInfo *lpVersionInformation);
 
 #if defined(__GCC_ASM_FLAG_OUTPUTS__) && !defined(__STRICT_ANSI__)
 #define IsAtLeastWindows10() (GetNtMajorVersion() >= 10)
+#define IsAtleastWindows8p1() \
+  (GetNtMajorVersion() > 6 || (GetNtMajorVersion() == 6 && GetNtMinorVersion() == 3))
 #define GetNtMajorVersion()    \
   ({                           \
     uintptr_t __x;             \
@@ -17,6 +19,14 @@ bool32 GetVersionEx(struct NtOsVersionInfo *lpVersionInformation);
         : "=q"(__x));          \
     (unsigned char)__x;        \
   })
+#define GetNtMinorVersion()    \
+  ({                           \
+    uintptr_t __x;             \
+    asm("mov\t%%gs:96,%q0\r\n" \
+        "mov\t284(%q0),%b0"    \
+        : "=q"(__x));          \
+    (unsigned char)__x;        \
+  })
 #endif
 
 COSMOPOLITAN_C_END_
diff --git a/libc/runtime/memtrack.internal.h b/libc/runtime/memtrack.internal.h
index c85878fdd..fe9ba0dd0 100644
--- a/libc/runtime/memtrack.internal.h
+++ b/libc/runtime/memtrack.internal.h
@@ -7,7 +7,6 @@
 #include "libc/macros.internal.h"
 #include "libc/thread/tls.h"
 #include "libc/nt/version.h"
-#include "libc/nt/enum/version.h"
 #include "libc/runtime/stack.h"
 #include "libc/sysv/consts/ss.h"
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
@@ -39,7 +38,7 @@ COSMOPOLITAN_C_START_
 #define _kMem(NORMAL, WIN7) \
   (!IsWindows() || IsAtLeastWindows10() ? NORMAL : WIN7)
 #define _kMemVista(NORMAL, WINVISTA) \
-  (!IsWindows() || NtGetVersion() >= kNtVersionWindows81 ? NORMAL : WINVISTA)
+  (!IsWindows() || IsAtleastWindows8p1() ? NORMAL : WINVISTA)
 
 struct MemoryInterval {
   int x;