Intel TurboBoost in practice
rwatson at FreeBSD.org
Mon Jul 26 12:19:37 UTC 2010
On Sun, 25 Jul 2010, Alexander Motin wrote:
>> The numbers that you are showing doesn't show much difference. Have you
>> tried buildworld?
> If you mean relative difference -- as I have told, it's mostly because of my
> CPU. It's maximal boost is 266MHz (8.3%), but 133MHz of them is enabled most
> of time if CPU is not overheated. It probably doesn't, as it works on clear
> table under air conditioner. So maximal effect I can expect on is 4.2%. In
> such situation 2.8% probably not so bad to illustrate that feature works and
> there is space for further improvements. If I had Core i5-750S I would
> expect 33% boost.
Can I recommend the use of ministat(1) and sample sizes of at least 8 runs per
> If you mean absolute difference, here are results or four buildworld runs:
> hw.acpi.cpu.cx_lowest=C1: 4654.23 sec
> hw.acpi.cpu.cx_lowest=C2: 4556.37 sec
> hw.acpi.cpu.cx_lowest=C2: 4570.85 sec
> hw.acpi.cpu.cx_lowest=C1: 4679.83 sec
> Benefit is about 2.1%. Each time results were erased and sources
> pre-cached into RAM. Storage was SSD, so disk should not be an issue.
> Alexander Motin
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