diff --git a/src/system/boot/arch/x86/cpu.cpp b/src/system/boot/arch/x86/cpu.cpp
index 3541daf6c7..9843a6cf76 100644
--- a/src/system/boot/arch/x86/cpu.cpp
+++ b/src/system/boot/arch/x86/cpu.cpp
@@ -304,7 +304,8 @@ slower_sample:
 extern "C" bigtime_t
 system_time()
 {
-	return rdtsc() * gTimeConversionFactor;
+	uint128 tsc(rdtsc());
+	return uint64((tsc * gTimeConversionFactor) >> 32);
 }