Thermal Throttling

[B Lo]

Hey folks. I just got around to further overclocking my P4 520 (2.8Ghz native). I got the FSB up to 235, resulting in a 3.3Ghz processor. However, even when I set thermal throttling to "disable" on my Abit AA8 Durmax board with the latest bios revision, I think it still remains active.

Around the upper 50s, when running Prime95, I notice that CPU utilization drops to 50 then 52 then 50 percent for the remainder. Why is this?

Is there some way around it?

One last thing, what is the most conservative guess for a safe temp to bring this chip to? I'd assume anything under 65 at load is safe. Right?

Well lemme know what you folks think. Thanks!

 

[B Lo]

Hey guys. I found the answer (I think) to my question. This is really cool, so read on. The issue was not truly one of thermal throttling, as that only occurs at much higher temperatures to such an extent (correct me anytime guys). I learned that with HT enabled in the BIOS that Windows, for purposes of listing CPU utilization considers (wait before attacking me) there to be two CPUs IN THAT the sum of the utilization of the CPUs is averaged. So to clarify, Windows sees the CPU and the "virtual CPU." Since Prime95 basically utilizes all of the CPU, it runs at 100% while the "virtual CPU" runs at close to 0, because there are no free clock cycles for it to pick up (read up on HT if you're unfamiliar with what I'm talking about or post a ?). The occasional 52% that I got was from the occasional use of HT in Prime95.

If this isn't written very clearly, please forgive me, as I am a little elated that I've upped my OC again at stock voltages by playing with the settings. Yay.

 

[zakee00]

good luck man

 

[Sc4freak]

Originally posted by: B Lo
Hey guys. I found the answer (I think) to my question. This is really cool, so read on. The issue was not truly one of thermal throttling, as that only occurs at much higher temperatures to such an extent (correct me anytime guys). I learned that with HT enabled in the BIOS that Windows, for purposes of listing CPU utilization considers (wait before attacking me) there to be two CPUs IN THAT the sum of the utilization of the CPUs is averaged. So to clarify, Windows sees the CPU and the "virtual CPU." Since Prime95 basically utilizes all of the CPU, it runs at 100% while the "virtual CPU" runs at close to 0, because there are no free clock cycles for it to pick up (read up on HT if you're unfamiliar with what I'm talking about or post a ?). The occasional 52% that I got was from the occasional use of HT in Prime95.

If this isn't written very clearly, please forgive me, as I am a little elated that I've upped my OC again at stock voltages by playing with the settings. Yay.

This has always been the case. Open Task Manager, and run a non-multithreaded program. The CPU usage will hover around 50% due to the fact that the program can only utilize one (virtual) CPU at a time.

If your chip is throttling, then the CPU usage will not drop. Neither will the clockspeed (unless you have the E0 stepping). You will just see degraded performance with your CPU. There is a program call ThrottleWatch somewhere on the internet, and it shows if you are throttling or not, and how much.

So many people complain about the Prescott throttling, but I have never, ever experienced my 4.0ghz clocked chip throttling.