Real Temp - New temp program for Intel Core processors

[unclewebb]

Falkentyne: I don't yet know if your problem is a RealTemp problem or maybe a problem with your CPU when overclocking. The number of people that have reported problems with the Load meter is very limited and during my testing when running 4 threads of Prime95 Small FFTs, it consistently shows in the high 99% range. When I recently did some testing for darkzone using Server 2008 HPC, on the same CPU it got as high as 100.0%. When I run 1, 2 or 3 threads of Prime, I get 25%, 50% or 75% more or less and it stays very consistently at those numbers unless something in the background kicks in and it briefly goes higher.

Use Prime95 Small FFTs when testing because I know the load it produces is very consistent. Are your percentage numbers consistent when you are running Prime95 Small FFTs? When you are overclocking to a higher MHz, does the Load meter initially start out at ~99% and then drop to 89% or 74% and then remain consistent at this amount or does it immediately only go to 74%?

There is a feature within Intel CPUs called Clock Modulation that can become automatically activated either by software or it can also become activated internally by the CPU itself. The percentage numbers you've mentioned have me wondering if maybe something like that is going on. Run Prime95 Small FFTs and go into the Settings window and you can play around with software activated Clock Modulation. The percentage numbers listed (87.5%, 75.0%, 62.5%, etc.) are Intel's approximations from their documentation. Depending on what multiplier your processor has, what you actually end up with will be different and won't equal those numbers.

My Q6600 has a 9.0 multi by default. My Load meter when playing with Clock Modulation will go from 99% to 88%, 77%, 65%, 55%, 45%,... Those first 6 steps seem to correspond pretty closely to 9/9, 8/9, 7/9, 6/9, 5/9 and 4/9. The last two steps I get are more like 3.5/9 and 2.5/9.

When Clock Modulation is activated on my Q6600, for every 9 pulses of the clock generator, 1 or more pulses gets ignored depending on how much modulation is being used. Programs like CPU-Z and RealTemp will still show your CPU running at full MHz but internally the CPU is acting sort of like a heart that is skipping a beat. This causes the CPU to run cooler since internally it's really not doing the same amount of work as a similar processor running at that same MHz which doesn't have any Clock Modulation going on.

Here's an example of my CPU at full load with no Clock Modulation:



When I set Clock Modulation to 50%, that seems to be equivalent to a load of about 5/9 or 55.5%.



The Task Manager and other traditional load meters continue to report this CPU working at 100% when internally speaking, it's only working half that hard.

It's obvious that this CPU is not working as hard because the average core temperature has dropped by about 10C compared to the first picture. The Task Manager continuing to report 100% Load does not accurately reflect what this CPU is doing while in this case, RealTemp does.

Do some testing and see if your RealTemp reported Load percentages correspond closely to what you'd get if you manually set Clock Modulation.

It's possible that this is nothing more than a big RealTemp bug but it's also possible that Clock Modulation is going on internally within your processor when you are overclocking. It's just a theory but it looks like the harder you push it, the more modulation kicks in.

I'll read the documentation and see if I can find a way to read the internal Clock Modulation status of a CPU. I think the user Clock Modulation and the hardware Clock Modulation are reported in separate registers. This bug is even more interesting than the last one.

Edit:

Model Specific Register (MSR) 0x19A is where software Clock Modulation data is stored within your CPU. User clock modulation is stored in the lower 5 bits. The upper bits are listed as Reserved by Intel but when your processor is reporting some lower than expected Load numbers in RealTemp, try doing a Read MSR on 0x19A. I don't know if it will show us anything but it's worth a look.

You can use my MSR tool for that:
http://www.fileden.com/files/2008/3/3/1794507/MSR.zip



You can click on the Read MSR button as much as you like and you won't hurt anything. If you enter random data into those two white boxes and go to different MSRs and click on Write MSR then you might get lucky and crash your computer. If that did happen, after you re-booted, everything would be back to normal so no worries.

Also try turning off TM1/TM2 in the bios when testing to see if that makes any difference when you're testing.