How to enable CPU turbo mode on FreeBSD?

Pierre-Luc Drouin pldrouin at
Fri Sep 11 01:14:55 UTC 2009


I have an overclocked i7 920 CPU for which I have enabled Turbo Mode in 
the BIOS (21x multiplier). The base clock is set at 190 MHz, so the CPU 
frequency with Turbo mode activated should be 3990 MHz. However the 
maximum value FreeBSD amd64 shows for the CPU frequency in dmesg and 
sysctl is 3790 MHz. How can I enable the Turbo Mode?

CPU: Intel(R) Core(TM) i7 CPU         920  @ 2.67GHz (3790.52-MHz 
K8-class CPU)

machdep.acpi_timer_freq: 3579545
machdep.tsc_freq: 3790522507
machdep.i8254_freq: 1193182
dev.cpu.0.freq: 349
dev.cpu.0.freq_levels: 2793/130000 2443/113750 2094/97500 1745/81250 
1396/65000 1047/48750 698/32500 349/16250


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