diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 4a0895b..8b29928 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -394,9 +394,9 @@ void __init time_init(void)
 	}
 
 	cpu_khz = tsc_khz;
-	if (cpu_has(&boot_cpu_data, X86_FEATURE_CONSTANT_TSC) &&
-		boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
+	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
 		boot_cpu_data.x86 == 16)
+		/* AMD Family 0x10 processors have a constant tsc */
 		cpu_khz = tsc_calibrate_cpu_khz();
 
 	if (unsynchronized_tsc())