diff --git a/core/sync/futex_windows.odin b/core/sync/futex_windows.odin
index 1c9d8b845..ce662ba9e 100644
--- a/core/sync/futex_windows.odin
+++ b/core/sync/futex_windows.odin
@@ -5,28 +5,28 @@ package sync
 import "core:time"
 
 foreign import Synchronization "system:Synchronization.lib"
-
 @(default_calling_convention="stdcall")
 foreign Synchronization {
-	WaitOnAddress       :: proc(Address: rawptr, CompareAddress: rawptr, AddressSize: uint, Timeout: u32) -> b32 ---
 	WakeByAddressSingle :: proc(Address: rawptr) ---
 	WakeByAddressAll    :: proc(Address: rawptr) ---
 }
 
-
+foreign import Ntdll "system:Ntdll.lib"
+@(default_calling_convention="stdcall")
+foreign Ntdll {
+	RtlWaitOnAddress :: proc(Address: rawptr, CompareAddress: rawptr, AddressSize: uint, Timeout: ^i64) -> i32 ---
+}
 
 _futex_wait :: proc(f: ^Futex, expect: u32) -> bool {
 	expect := expect
-	return bool(WaitOnAddress(f, &expect, size_of(expect), ~u32(0)))
+	return 0 == RtlWaitOnAddress(f, &expect, size_of(expect), nil)
 }
 
 _futex_wait_with_timeout :: proc(f: ^Futex, expect: u32, duration: time.Duration) -> bool {
 	expect := expect
-	timeout := u32(0)
-	if duration > 0 {
-		timeout = u32(duration/1e6)
-	}
-	return bool(WaitOnAddress(f, &expect, size_of(expect), timeout))
+	// NOTE(bill): for some bizarre reason, this has be a negative number
+	timeout := -i64(duration / 100)
+	return 0 == RtlWaitOnAddress(f, &expect, size_of(expect), &timeout)
 }
 
 _futex_signal :: proc(f: ^Futex) {