Index: trunk/i386/libsaio/cpu.c
===================================================================
--- trunk/i386/libsaio/cpu.c	(revision 1196)
+++ trunk/i386/libsaio/cpu.c	(revision 1197)
@@ -463,15 +463,19 @@
                 
             case 0x01: /* K10 */
                 msr = rdmsr64(K10_COFVID_STATUS);
-                //uint64_t mperf = measure_mperf_frequency();
-                uint64_t aperf = measure_aperf_frequency();
+                do_cpuid2(0x00000006, 0, p->CPU.CPUID[CPUID_6]);
+                if(bitfield(p->CPU.CPUID[CPUID_6][2], 0, 0) == 1)   // EffFreq: effective frequency interface
+                {
+                    //uint64_t mperf = measure_mperf_frequency();
+                    uint64_t aperf = measure_aperf_frequency();
+                    cpuFrequency = aperf;
+                }
                 // NOTE: tsc runs at the maccoeff (non turbo)
                 //          *not* at the turbo frequency.
                 maxcoef  = bitfield(msr, 54, 49) / 2 + 4;
                 currcoef = bitfield(msr, 5, 0) + 0x10;
                 currdiv = 2 << bitfield(msr, 8, 6);
                 
-                cpuFrequency = aperf;
                 break;
                 
             case 0x05: /* K14 */
Index: trunk/i386/libsaio/platform.h
===================================================================
--- trunk/i386/libsaio/platform.h	(revision 1196)
+++ trunk/i386/libsaio/platform.h	(revision 1197)
@@ -23,10 +23,11 @@
 #define CPUID_2				2
 #define CPUID_3				3
 #define CPUID_4				4
-#define CPUID_80			5
-#define CPUID_81			6
-#define CPUID_88			7
-#define CPUID_MAX			8
+#define CPUID_6				5
+#define CPUID_80			6
+#define CPUID_81			7
+#define CPUID_88			8
+#define CPUID_MAX			9
 
 #define CPU_MODEL_YONAH			0x0E			// Sossaman, Yonah
 #define CPU_MODEL_MEROM			0x0F			// Allendale, Conroe, Kentsfield, Woodcrest, Clovertown, Tigerton, Merom