diff --git a/sys/x86/x86/tsc.c b/sys/x86/x86/tsc.c
index 2a6c81d..a30424e 100644
--- a/sys/x86/x86/tsc.c
+++ b/sys/x86/x86/tsc.c
@@ -57,7 +57,8 @@ int		tsc_perf_stat;
 static eventhandler_tag tsc_levels_tag, tsc_pre_tag, tsc_post_tag;
 
 SYSCTL_INT(_kern_timecounter, OID_AUTO, invariant_tsc, CTLFLAG_RDTUN,
-    &tsc_is_invariant, 0, "Indicates whether the TSC is P-state invariant");
+    &tsc_is_invariant, 0,
+    "Indicates whether the TSC is ACPI P-, C- and T-state invariant");
 TUNABLE_INT("kern.timecounter.invariant_tsc", &tsc_is_invariant);
 
 #ifdef SMP
@@ -272,9 +273,7 @@ probe_tsc_freq(void)
 
 	switch (cpu_vendor_id) {
 	case CPU_VENDOR_AMD:
-		if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0 ||
-		    (vm_guest == VM_GUEST_NO &&
-		    CPUID_TO_FAMILY(cpu_id) >= 0x10))
+		if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0)
 			tsc_is_invariant = 1;
 		if (cpu_feature & CPUID_SSE2) {
 			tsc_timecounter.tc_get_timecount =
@@ -282,12 +281,7 @@ probe_tsc_freq(void)
 		}
 		break;
 	case CPU_VENDOR_INTEL:
-		if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0 ||
-		    (vm_guest == VM_GUEST_NO &&
-		    ((CPUID_TO_FAMILY(cpu_id) == 0x6 &&
-		    CPUID_TO_MODEL(cpu_id) >= 0xe) ||
-		    (CPUID_TO_FAMILY(cpu_id) == 0xf &&
-		    CPUID_TO_MODEL(cpu_id) >= 0x3))))
+		if ((amd_pminfo & AMDPM_TSC_INVARIANT) != 0)
 			tsc_is_invariant = 1;
 		if (cpu_feature & CPUID_SSE2) {
 			tsc_timecounter.tc_get_timecount =
@@ -554,20 +548,6 @@ init_TSC_tc(void)
 	}
 
 	/*
-	 * We cannot use the TSC if it stops incrementing in deep sleep.
-	 * Currently only Intel CPUs are known for this problem unless
-	 * the invariant TSC bit is set.
-	 */
-	if (cpu_can_deep_sleep && cpu_vendor_id == CPU_VENDOR_INTEL &&
-	    (amd_pminfo & AMDPM_TSC_INVARIANT) == 0) {
-		tsc_timecounter.tc_quality = -1000;
-		tsc_timecounter.tc_flags |= TC_FLAGS_C3STOP;
-		if (bootverbose)
-			printf("TSC timecounter disabled: C3 enabled.\n");
-		goto init;
-	}
-
-	/*
 	 * We can not use the TSC in SMP mode unless the TSCs on all CPUs
 	 * are synchronized.  If the user is sure that the system has
 	 * synchronized TSCs, set kern.timecounter.smp_tsc tunable to a