On Jan 21, 9:51 am, "David J Taylor" <[email protected] this-bit.and-this-part.co.uk.invalid> wrote: > > Thanks, Martin. I'm beginning to wish I'd never asked, as I have Windows > XP SP3 here and yet the performance counter is running at 2.4GHz (Intel > E6600 dual-core). Or does the PM_Timer only apply to AMD systems?
Windows chooses the most precise, invariant frequency source available in the system. As I said before, Intel's Core2 processors have a TSC that doesn't vary with the CPU clock (though its precision is not as good as it seems). Only newer AMD processors sport the same feature and even then it must be enabled by a BIOS option that's not always available. Therefore, the likelihood of an AMD system using the PM timer is greater than new Intel systems. In these days, it's moot to worry about the precision of the QueryPerformanceCounter function. Windows will use the most precise time source in the system and only very old systems would not have at least the PM timer. HTH _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
