http://www.fileden.com/files/2008/3/3/1794507/Turbo.zip
This new tool follows the method outlined in the Intel Turbo white paper for Core i7 and at full load is the most accurate method to calculate the CPU multiplier.
The reason this is important is that some motherboards at full load running high stress programs like LinX will start to cycle the Turbo (+1 multiplier) feature on and off rapidly. This new i7 Turbo tool should catch that situation sooner than any other software presently available. At full load, as soon as the calculated multiplier starts to drop, Turbo mode is starting to cycle on and off.
Most software only reads a single multiplier value from a model specific register (MSR) within the CPU. This is not the preferred method.
If you notice a lot of drift in the calculated multiplier at idle, that's a sign that your bios settings for EIST and C1E do not agree with your Windows Power Options settings. In Vista you need to go into the Control Panel -> Power Options and set your Minimum processor state to the appropriate percentage to either fully enable or fully disable your energy saving features. Try using 50% or 100% for this setting. You may find that your bios version does not properly handle turning off some things like EIST if that is your goal.
Windows XP is a little different. To fully enable EIST and to get your computer to use a reduced multiplier at idle, (6.0 Core 2 / 12.0 Core i7), you might need to go into the Power Options and set the Power Scheme to Portable/Laptop computer.
If you have a Core i7 and enable Turbo mode in the bios, you can also use this tool to toggle Turbo mode on and off from within Windows.
This tool was designed for the Core i7 but I decided to support Core 2 processors as well. The method outlined in the Intel Turbo white paper also applies to the Core 2 CPUs that I've tested.
Here's a test I came up with to check how software deals with odd ball multipliers and situations that you don't read about in any book.
A Quad CPU has two Dual Core CPUs inside of it. Using MSR 0x199 you can trick it so that one of the Dual Cores uses one multiplier while the other Dual Core uses a completely different multiplier, even at full load running Prime95.
For my example I set core0 and core 1 to use a 9.0X multi and core2 and core3 to use a 6.0X multi. Right click on CPU-Z and you can get it to read any individual core.
CPU-Z correctly shows one side of the CPU running at 3000 MHz and the other side at 2000 MHz. RealTemp averages those two values and reports 2500 MHz. RealTemp also averages the 9.0 and 6.0 multipliers and displays 7.5.
The average multi read from the MSR is shown as 7.500 and the calculated multi also shows the correct 7.5000. Not a lot of tools can handle this situation correctly.
At idle, calculating the multiplier with Intel's method can result in the occasional random value but if your system is set up right, the amount of multiplier drift should be minimal.
At full load running Prime Small FFTs, the calculated multiplier should be steady as a rock. Any drift at full load is the first sign of a problem.
If you learn something new about your CPU using this tool then post your results. This is the first general release of i7 Turbo so if there are any problems or anything you don't understand, let me know. Thanks.
This new tool follows the method outlined in the Intel Turbo white paper for Core i7 and at full load is the most accurate method to calculate the CPU multiplier.
The reason this is important is that some motherboards at full load running high stress programs like LinX will start to cycle the Turbo (+1 multiplier) feature on and off rapidly. This new i7 Turbo tool should catch that situation sooner than any other software presently available. At full load, as soon as the calculated multiplier starts to drop, Turbo mode is starting to cycle on and off.
Most software only reads a single multiplier value from a model specific register (MSR) within the CPU. This is not the preferred method.
If you notice a lot of drift in the calculated multiplier at idle, that's a sign that your bios settings for EIST and C1E do not agree with your Windows Power Options settings. In Vista you need to go into the Control Panel -> Power Options and set your Minimum processor state to the appropriate percentage to either fully enable or fully disable your energy saving features. Try using 50% or 100% for this setting. You may find that your bios version does not properly handle turning off some things like EIST if that is your goal.
Windows XP is a little different. To fully enable EIST and to get your computer to use a reduced multiplier at idle, (6.0 Core 2 / 12.0 Core i7), you might need to go into the Power Options and set the Power Scheme to Portable/Laptop computer.
If you have a Core i7 and enable Turbo mode in the bios, you can also use this tool to toggle Turbo mode on and off from within Windows.
This tool was designed for the Core i7 but I decided to support Core 2 processors as well. The method outlined in the Intel Turbo white paper also applies to the Core 2 CPUs that I've tested.
Here's a test I came up with to check how software deals with odd ball multipliers and situations that you don't read about in any book.
A Quad CPU has two Dual Core CPUs inside of it. Using MSR 0x199 you can trick it so that one of the Dual Cores uses one multiplier while the other Dual Core uses a completely different multiplier, even at full load running Prime95.
For my example I set core0 and core 1 to use a 9.0X multi and core2 and core3 to use a 6.0X multi. Right click on CPU-Z and you can get it to read any individual core.
CPU-Z correctly shows one side of the CPU running at 3000 MHz and the other side at 2000 MHz. RealTemp averages those two values and reports 2500 MHz. RealTemp also averages the 9.0 and 6.0 multipliers and displays 7.5.
The average multi read from the MSR is shown as 7.500 and the calculated multi also shows the correct 7.5000. Not a lot of tools can handle this situation correctly.
At idle, calculating the multiplier with Intel's method can result in the occasional random value but if your system is set up right, the amount of multiplier drift should be minimal.
At full load running Prime Small FFTs, the calculated multiplier should be steady as a rock. Any drift at full load is the first sign of a problem.
If you learn something new about your CPU using this tool then post your results. This is the first general release of i7 Turbo so if there are any problems or anything you don't understand, let me know. Thanks.
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