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Windows 7: W7 Can't Stop CPU Throttling

07 May 2009   #21
johngalt

 

OK, get some sleep, and in the meantime I am installing 7 RC on two computers, my desktop (x64) and my laptop (x86) - let's see if I like it as much as I think I am going to....

or not.


My System SpecsSystem Spec
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07 May 2009   #22
Bilco

Windows 7 RC 1 7100//Win XPx32 SP3
 
 

Alright thanks for all the feedback. I'll c heck the 4 or 5 other places I posted this issue on tomorrow and see if i got any other feedback there.
My System SpecsSystem Spec
12 Jun 2009   #23
unclewebb

Vista
 
 

I wrote a program called i7 Turbo that lets you accurately monitor your multiplier.

http://www.fileden.com/files/2008/3/3/1794507/Turbo.zip

This download includes a small utility called MultiBoost.exe that might be able to help with this problem. It's made a few DFI owners happy!

If this works for you then you can also try the latest version of RealTemp 3.30 RC4 which includes this option. Just go into the RealTemp.INI file and add this:

MultiBoost=1

and it should help keep your multiplier at its maximum. You need Turbo and EIST enabled and that's about it. Give this thread a bump if this works for you.
My System SpecsSystem Spec
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12 Jun 2009   #24
Bilco

Windows 7 RC 1 7100//Win XPx32 SP3
 
 

Hmm according to your program the mult is at 21 like it is in the bios. Perhaps CPUID is inaccurate in W7?

I didn't bother following up with the realtemp and multiboost programs yet because if this is accurate then there is no need to. I have EIST and C1E disabled in the bios for OCing and to attempt to resolve this issue.

So according to this then, the mult is not actually fluctuating like CPUID reports?
My System SpecsSystem Spec
12 Jun 2009   #25
unclewebb

Vista
 
 

I decided to follow the method to calculate the multiplier as outlined in the Intel Turbo White Paper.

http://download.intel.com/design/pro...ots/320354.pdf

To the best of my knowledge, RealTemp and i7 Turbo are the only programs that are using the high performance timers within the CPU and following Intel's recommended method. It is a cumbersome method and there are definitely easier ways to read the multiplier but Intel's way is the most accurate.

I believe CPUID and CPU-Z are related and both use the same System Monitoring Development Kit.

CPUID Developers Corner

I have seen CPU-Z screen shots with multipliers of 2X or 3X which is impossible since the lowest multiplier on a Core i7 is 12X. I've also seen problems where 22X is reported on a 920 at idle even though EIST / SpeedStep is clearly working because of the large drop in core voltage. When the voltage drops, so does the multiplier.

Have a look in your Control Panel -> Power Options as well. In Windows 7 or Vista there is a setting in there called Minimum processor state. That, C1E and EIST all play a part in what multiplier you get at idle. Sometimes the wrong combination will cause your Calculated Multiplier to endlessly float somewhere around 16 or 17. This is a sign that one of these items is telling your CPU to drop the multiplier down to 12 while another setting is telling your CPU to use its full 21X multiplier. The end result is an average multiplier somewhere in the middle of these two numbers.

I included the Standard Deviation of the Calculated Multiplier in i7 Turbo. This is shown just below the Calculated Multiplier and gives you a good idea of how stable your multiplier really is. At full load this number should be zero. At idle, if your Calculated Multiplier is steady at 12, the Standard Deviation should also be very close to 0.000.

If you need any help understanding what these tools are telling you then just ask. I included the MSR multiplier in i7 Turbo. This is the typical way that most software determines the multiplier. It gives a snapshot of what the multiplier is at the particular instant that you read this value from the processor but doesn't always accurately reflect the true multiplier. Just reading the multiplier from a CPU can put a load on the CPU and change what the multiplier is. That's why Intel recommends the Calculated Multiplier.
My System SpecsSystem Spec
12 Jun 2009   #26
Bilco

Windows 7 RC 1 7100//Win XPx32 SP3
 
 

Quote   Quote: Originally Posted by unclewebb View Post
I decided to follow the method to calculate the multiplier as outlined in the Intel Turbo White Paper.

http://download.intel.com/design/pro...ots/320354.pdf

To the best of my knowledge, RealTemp and i7 Turbo are the only programs that are using the high performance timers within the CPU and following Intel's recommended method. It is a cumbersome method and there are definitely easier ways to read the multiplier but Intel's way is the most accurate.

I believe CPUID and CPU-Z are related and both use the same System Monitoring Development Kit.

CPUID Developers Corner

I have seen CPU-Z screen shots with multipliers of 2X or 3X which is impossible since the lowest multiplier on a Core i7 is 12X. I've also seen problems where 22X is reported on a 920 at idle even though EIST / SpeedStep is clearly working because of the large drop in core voltage. When the voltage drops, so does the multiplier.

Have a look in your Control Panel -> Power Options as well. In Windows 7 or Vista there is a setting in there called Minimum processor state. That, C1E and EIST all play a part in what multiplier you get at idle. Sometimes the wrong combination will cause your Calculated Multiplier to endlessly float somewhere around 16 or 17. This is a sign that one of these items is telling your CPU to drop the multiplier down to 12 while another setting is telling your CPU to use its full 21X multiplier. The end result is an average multiplier somewhere in the middle of these two numbers.

I included the Standard Deviation of the Calculated Multiplier in i7 Turbo. This is shown just below the Calculated Multiplier and gives you a good idea of how stable your multiplier really is. At full load this number should be zero. At idle, if your Calculated Multiplier is steady at 12, the Standard Deviation should also be very close to 0.000.

If you need any help understanding what these tools are telling you then just ask. I included the MSR multiplier in i7 Turbo. This is the typical way that most software determines the multiplier. It gives a snapshot of what the multiplier is at the particular instant that you read this value from the processor but doesn't always accurately reflect the true multiplier. Just reading the multiplier from a CPU can put a load on the CPU and change what the multiplier is. That's why Intel recommends the Calculated Multiplier.
So this tool i7Turbo is just a calculator estimator? It doesn't actually read and spit out numbers for the current multiplier? See the problem I'm experiencing is with EIST C1E Turbo disabled set at 21x in b ios and CPUID is showing my multiplier dropping as low as 4x in windows 7. Where in XP 32 SP3 CPUID displays a solid 21x the entire time. On a side note the voltage doesnt change in W7 CPUID as the multiplier fluctuates.
My System SpecsSystem Spec
13 Jun 2009   #27
unclewebb

Vista
 
 

Every program since the beginning of time has been misleading people about what their true multiplier really is.

i7 Turbo reads the internal timers within Core based CPUs and displays the Calculated multiplier in real time as recommended by Intel. The Calculated Multiplier is the REAL multiplier. Everything else is a phony approximation.

Once i7 Turbo was done, I transferred that code back into RealTemp so RealTemp also uses the proper method to report the correct multiplier. RealTemp has been using this method for Core i7 since it was first introduced months ago. Writing i7 Turbo helped me understand things better and I was able to make some improvements for better accuracy at idle.

Neither CPU-Z or CPUID seems to be following the Intel recommended method. You'll have to ask them why they don't. Windows 7 is exposing software that hasn't been following the proper procedure.

Any software that shows a 4X multiplier for a Core i7 CPU is wrong. The minimum multiplier for a Core i7 is 12.

Give i7 Turbo a try. If you don't understand what it is telling you then post some screen shots of it and CPUID or CPU-Z and I will explain what it's showing you. It will report the same info in any operating system as long as both operating systems and bioses are set up the same.
My System SpecsSystem Spec
13 Jun 2009   #28
unclewebb

Vista
 
 

Here's an explanation of what the calculated multiplier is all about.

Inside Intel Core based CPUs are two timers. The first timer is called the core timer and the second timer is called the ref or reference timer.

These timers run at millions of cycles per second at idle and billions of cycles per second at full load so using them to calculate the CPU multiplier is extremely accurate.

To determine the current multiplier of an Intel CPU, you monitor these two timers in real time and sample them once every second to see how many cycles each timer has counted since the last sample.

The number of core cycles divided by the number of ref cycles gives you a ratio. When both timers are running at the exact same speed, the ratio is 1:1 which means that your CPU is operating at its maximum multiplier. For a Core i7 920, that would be a multiplier of 20.0.

When you sample these two timers and divide core cycles by reference cycles and end up with a number greater than 1.00, that's a sign that the Turbo feature of your processor is engaged. For a Core i7 920, the ratio when Turbo is engaged is exactly 1.05. To calculate your multiplier you multiply the turbo ratio by your default multiplier. ie. 1.05 X 20.0 = 21.0

If you only have one core enabled in the bios, this ratio can go as high as 1.10. Your 920 is now operating with a CPU multiplier of 1.10 X 20.0 = 22.0

When EIST / Speedstep is enabled, this ratio will work out to be 0.60 for a 920 CPU. ie. 0.60 X 20.0 = 12.0 The core timer is moving at 60% of the speed that the reference timer is moving at.

Using these timers in this manner and constantly comparing the rate at which they are changing is the only accurate way to calculate the average multiplier and is the way that Intel recommends.

For a Core i7 there are 8 threads and two timers for each thread so software would need to manage 16 individual timers. Most software cheats and instead of accurately calculating the multiplier with this method, they read the current multiplier from a single register within the CPU. This method is so much easier but is not nearly as accurate, especially when a CPU is lightly loaded.



This picture of i7 Turbo shows that both the Calculated Multiplier and the traditional multiplier based on reading a Model Specific Register (MSR) within the CPU are in agreement. Below the Calculated Multiplier is the standard deviation which lets you know how closely all 8 threads are reporting their multiplier. A reading of 0.000 shows that they are all in agreement. When the multiplier is rapidly changing, the standard deviation will increase showing that in the time it takes to read all 8 multipliers, they are changing rapidly. The multiplier can change thousands of times a second. Reading one MSR register once per second only gives you a very limited snapshot of what the actual multiplier really is. Only the calculated multiplier can tell you exactly what's going on inside your CPU.
My System SpecsSystem Spec
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 W7 Can't Stop CPU Throttling




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