Simple question really. I have an i7 930 and have had HT turned on for the entire time I've owned it, as it comes turned on by default. I've tried turning it off and my temperatures are significantly lower. Will I loose PPD by turning it off?
If you are running an SMP client, especially with the bonus system where speed is important, then I believe HT does help, as the client sees more "cores" - real or virtual. Some people report an increase in PPD by running the client with one core fewer, so -smp 7 rather than -smp 8 (though there is a suggestion that this only applies to AMD processors). Try it, see what PPD you get with HT turned on and off. Turning HT off is known to lower the temperatures, whether you can then regain the PPD by overclocking seems unlikely to me. Recent Intel CPUs are fairly rugged, and should be able to stand up to a high running temperature for long periods. I've seen suggestions of maximum sustained temperatures of anywhere between 69C and 80C. Do these shorten the lifetime? In theory yes, in practice, how long before you upgrade? I reckon the motherboard components are the weakest link.
Hyper-Threading will boost your ppd on a Core i7, particularly with the A3 version of the SMP CPU client, so is definitely worth turning on.
Yeah like Lizard says HT deffo gives bit of a PPD boost but yes you do get slightly higher temps, what cooler you using and what temps are you seeing out of interest Pha4ZeD?
I'm currently stress testing at 3.7GHz with a Titan Fenrir cooler, with HT disabled. I have load temps of 60C on core 0 to 56C on core 3. EDIT: This is at 1.225V with over an hour Prime95. Going to leave it a few more hours and hopefully its completely stable, meaning I can move onto 3.8GHz+
you should be able to hit 4.0 @ around 1.35 vcore does your case move a lot of air? depending on how much gaming you do bigadv is easyer to setup than the smp client and worth maximum ppd im getting 24000ppd with a i7-860@4.0 181X22 + the 8000ppd i get from my gtx-260 650/1540/1100
