CPU not running at full speed in Ubuntu

Got a QX6700, CPU-Z reports 2.66GHz in Windows, but under Ubuntu Hardy, /proc/cpuinfo reports this:

Code:

processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Core(TM)2 Quad CPU @ 2.66GHz stepping : 7 cpu MHz : 1602.000 cache size : 4096 KB physical id : 0 siblings : 4 core id : 0 cpu cores : 4 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm bogomips : 5349.46 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: processor : 1 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Core(TM)2 Quad CPU @ 2.66GHz stepping : 7 cpu MHz : 1602.000 cache size : 4096 KB physical id : 0 siblings : 4 core id : 3 cpu cores : 4 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm bogomips : 5345.47 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: processor : 2 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Core(TM)2 Quad CPU @ 2.66GHz stepping : 7 cpu MHz : 1602.000 cache size : 4096 KB physical id : 0 siblings : 4 core id : 1 cpu cores : 4 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm bogomips : 5345.49 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: processor : 3 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Core(TM)2 Quad CPU @ 2.66GHz stepping : 7 cpu MHz : 1602.000 cache size : 4096 KB physical id : 0 siblings : 4 core id : 2 cpu cores : 4 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm bogomips : 5345.44 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management:

Any ideas what's up there? EIST and C1E are off.

CPU is sat in an Abit IX38 QuadGT with the latest BIOS.