diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index c86507178047..2afe59a3e329 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -35,7 +35,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)machdep.c	7.4 (Berkeley) 6/3/91
- *	$Id: machdep.c,v 1.48 1994/08/10 03:51:07 wollman Exp $
+ *	$Id: machdep.c,v 1.49 1994/08/10 03:53:33 wollman Exp $
  */
 
 #include "npx.h"
@@ -179,6 +179,7 @@ cpu_startup()
 	 * Good {morning,afternoon,evening,night}.
 	 */
 	printf(version);
+	startrtclock();
 	identifycpu();
 	printf("real memory  = %d (%d pages)\n", ptoa(physmem), physmem);
 	if (badpages)
@@ -387,6 +388,14 @@ identifycpu()
 		printf("unknown");	/* will panic below... */
 	}
 	printf("-class CPU)");
+#ifdef I586_CPU
+	if(cpu_class == CPUCLASS_586) {
+		extern void calibrate_cyclecounter();
+		extern int pentium_mhz;
+		calibrate_cyclecounter();
+		printf(" %d MHz", pentium_mhz);
+	}
+#endif
 	if(cpu_id)
 		printf("  Id = 0x%x",cpu_id);
 	if(*cpu_vendor)
diff --git a/sys/amd64/amd64/tsc.c b/sys/amd64/amd64/tsc.c
index e40079a40bea..3c2391991c1b 100644
--- a/sys/amd64/amd64/tsc.c
+++ b/sys/amd64/amd64/tsc.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.6 1994/02/06 22:48:13 davidg Exp $
+ *	$Id: clock.c,v 1.10 1994/05/25 08:58:32 rgrimes Exp $
  */
 
 /*
@@ -181,6 +181,28 @@ getit()
 	return ((high << 8) | low);
 }
 
+#ifdef I586_CPU
+int pentium_mhz = 0;
+static long long cycles_per_sec = 0;
+
+void
+calibrate_cyclecounter(void)
+{
+	volatile long edx, eax, lasteax, lastedx;
+
+	__asm __volatile(".byte 0x0f, 0x31" : "=a"(lasteax), "=d"(lastedx) : );
+	DELAY(1000000);
+	__asm __volatile(".byte 0x0f, 0x31" : "=a"(eax), "=d"(edx) : );
+
+	/*
+	 * This assumes that you will never have a clock rate higher
+	 * than 4GHz, probably a good assumption.
+	 */
+	cycles_per_sec = (long long)edx + eax;
+	cycles_per_sec -= (long long)lastedx + lasteax;
+	pentium_mhz = ((long)cycles_per_sec + 500000) / 1000000; /* round up */
+}
+#endif
 
 /*
  * Wait "n" microseconds.
@@ -432,7 +454,6 @@ spinwait(int millisecs)
 void
 cpu_initclocks()
 {
-	startrtclock();
 	enablertclock();
 }
 
diff --git a/sys/amd64/isa/clock.c b/sys/amd64/isa/clock.c
index e40079a40bea..3c2391991c1b 100644
--- a/sys/amd64/isa/clock.c
+++ b/sys/amd64/isa/clock.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.6 1994/02/06 22:48:13 davidg Exp $
+ *	$Id: clock.c,v 1.10 1994/05/25 08:58:32 rgrimes Exp $
  */
 
 /*
@@ -181,6 +181,28 @@ getit()
 	return ((high << 8) | low);
 }
 
+#ifdef I586_CPU
+int pentium_mhz = 0;
+static long long cycles_per_sec = 0;
+
+void
+calibrate_cyclecounter(void)
+{
+	volatile long edx, eax, lasteax, lastedx;
+
+	__asm __volatile(".byte 0x0f, 0x31" : "=a"(lasteax), "=d"(lastedx) : );
+	DELAY(1000000);
+	__asm __volatile(".byte 0x0f, 0x31" : "=a"(eax), "=d"(edx) : );
+
+	/*
+	 * This assumes that you will never have a clock rate higher
+	 * than 4GHz, probably a good assumption.
+	 */
+	cycles_per_sec = (long long)edx + eax;
+	cycles_per_sec -= (long long)lastedx + lasteax;
+	pentium_mhz = ((long)cycles_per_sec + 500000) / 1000000; /* round up */
+}
+#endif
 
 /*
  * Wait "n" microseconds.
@@ -432,7 +454,6 @@ spinwait(int millisecs)
 void
 cpu_initclocks()
 {
-	startrtclock();
 	enablertclock();
 }
 
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index c86507178047..2afe59a3e329 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -35,7 +35,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)machdep.c	7.4 (Berkeley) 6/3/91
- *	$Id: machdep.c,v 1.48 1994/08/10 03:51:07 wollman Exp $
+ *	$Id: machdep.c,v 1.49 1994/08/10 03:53:33 wollman Exp $
  */
 
 #include "npx.h"
@@ -179,6 +179,7 @@ cpu_startup()
 	 * Good {morning,afternoon,evening,night}.
 	 */
 	printf(version);
+	startrtclock();
 	identifycpu();
 	printf("real memory  = %d (%d pages)\n", ptoa(physmem), physmem);
 	if (badpages)
@@ -387,6 +388,14 @@ identifycpu()
 		printf("unknown");	/* will panic below... */
 	}
 	printf("-class CPU)");
+#ifdef I586_CPU
+	if(cpu_class == CPUCLASS_586) {
+		extern void calibrate_cyclecounter();
+		extern int pentium_mhz;
+		calibrate_cyclecounter();
+		printf(" %d MHz", pentium_mhz);
+	}
+#endif
 	if(cpu_id)
 		printf("  Id = 0x%x",cpu_id);
 	if(*cpu_vendor)
diff --git a/sys/i386/i386/tsc.c b/sys/i386/i386/tsc.c
index e40079a40bea..3c2391991c1b 100644
--- a/sys/i386/i386/tsc.c
+++ b/sys/i386/i386/tsc.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.6 1994/02/06 22:48:13 davidg Exp $
+ *	$Id: clock.c,v 1.10 1994/05/25 08:58:32 rgrimes Exp $
  */
 
 /*
@@ -181,6 +181,28 @@ getit()
 	return ((high << 8) | low);
 }
 
+#ifdef I586_CPU
+int pentium_mhz = 0;
+static long long cycles_per_sec = 0;
+
+void
+calibrate_cyclecounter(void)
+{
+	volatile long edx, eax, lasteax, lastedx;
+
+	__asm __volatile(".byte 0x0f, 0x31" : "=a"(lasteax), "=d"(lastedx) : );
+	DELAY(1000000);
+	__asm __volatile(".byte 0x0f, 0x31" : "=a"(eax), "=d"(edx) : );
+
+	/*
+	 * This assumes that you will never have a clock rate higher
+	 * than 4GHz, probably a good assumption.
+	 */
+	cycles_per_sec = (long long)edx + eax;
+	cycles_per_sec -= (long long)lastedx + lasteax;
+	pentium_mhz = ((long)cycles_per_sec + 500000) / 1000000; /* round up */
+}
+#endif
 
 /*
  * Wait "n" microseconds.
@@ -432,7 +454,6 @@ spinwait(int millisecs)
 void
 cpu_initclocks()
 {
-	startrtclock();
 	enablertclock();
 }
 
diff --git a/sys/i386/isa/clock.c b/sys/i386/isa/clock.c
index e40079a40bea..3c2391991c1b 100644
--- a/sys/i386/isa/clock.c
+++ b/sys/i386/isa/clock.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.6 1994/02/06 22:48:13 davidg Exp $
+ *	$Id: clock.c,v 1.10 1994/05/25 08:58:32 rgrimes Exp $
  */
 
 /*
@@ -181,6 +181,28 @@ getit()
 	return ((high << 8) | low);
 }
 
+#ifdef I586_CPU
+int pentium_mhz = 0;
+static long long cycles_per_sec = 0;
+
+void
+calibrate_cyclecounter(void)
+{
+	volatile long edx, eax, lasteax, lastedx;
+
+	__asm __volatile(".byte 0x0f, 0x31" : "=a"(lasteax), "=d"(lastedx) : );
+	DELAY(1000000);
+	__asm __volatile(".byte 0x0f, 0x31" : "=a"(eax), "=d"(edx) : );
+
+	/*
+	 * This assumes that you will never have a clock rate higher
+	 * than 4GHz, probably a good assumption.
+	 */
+	cycles_per_sec = (long long)edx + eax;
+	cycles_per_sec -= (long long)lastedx + lasteax;
+	pentium_mhz = ((long)cycles_per_sec + 500000) / 1000000; /* round up */
+}
+#endif
 
 /*
  * Wait "n" microseconds.
@@ -432,7 +454,6 @@ spinwait(int millisecs)
 void
 cpu_initclocks()
 {
-	startrtclock();
 	enablertclock();
 }
 
diff --git a/sys/isa/atrtc.c b/sys/isa/atrtc.c
index e40079a40bea..3c2391991c1b 100644
--- a/sys/isa/atrtc.c
+++ b/sys/isa/atrtc.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.6 1994/02/06 22:48:13 davidg Exp $
+ *	$Id: clock.c,v 1.10 1994/05/25 08:58:32 rgrimes Exp $
  */
 
 /*
@@ -181,6 +181,28 @@ getit()
 	return ((high << 8) | low);
 }
 
+#ifdef I586_CPU
+int pentium_mhz = 0;
+static long long cycles_per_sec = 0;
+
+void
+calibrate_cyclecounter(void)
+{
+	volatile long edx, eax, lasteax, lastedx;
+
+	__asm __volatile(".byte 0x0f, 0x31" : "=a"(lasteax), "=d"(lastedx) : );
+	DELAY(1000000);
+	__asm __volatile(".byte 0x0f, 0x31" : "=a"(eax), "=d"(edx) : );
+
+	/*
+	 * This assumes that you will never have a clock rate higher
+	 * than 4GHz, probably a good assumption.
+	 */
+	cycles_per_sec = (long long)edx + eax;
+	cycles_per_sec -= (long long)lastedx + lasteax;
+	pentium_mhz = ((long)cycles_per_sec + 500000) / 1000000; /* round up */
+}
+#endif
 
 /*
  * Wait "n" microseconds.
@@ -432,7 +454,6 @@ spinwait(int millisecs)
 void
 cpu_initclocks()
 {
-	startrtclock();
 	enablertclock();
 }