jy_nz: i7 Turbo seems to be working correctly and will give you the most accurate look at your multiplier. This tool also works on Core 2 CPUs.
Your screen shot shows that you are running a single threaded task which is being mostly shared between the two center cores. The two outside cores are in charge of running any background tasks while this is going on.
On a Core i5 750, you will get a 24 multiplier but you only get this when 1 core is active. The two center cores are taking turns as the active core while the two outside cores are spending most of their time asleep.
I don't have the official specs yet but I'll post a utility that you can use to confirm your CPU's capabilities in a moment.
As soon as 2 cores are active, your CPU will no longer be able to use the 24X multiplier. When all 4 cores are active, your maximum multiplier is 21. The Load Filter setting in i7 Turbo limits the data going into the Min and Max boxes. In your screen shot you have this set to 95% (the default) so it is recording the min and max multiplier only when your load is over 95%. If you change this filter to 0%, then all data will be considered for the Min and Max statistics. That's why it is only showing 21.000 because at full load, greater than 95%, that's all this CPU can do.
The 23.733 and 23.829 values for the two center cores are a very accurate average of the multipliers for those two cores during the previous 1 second interval. What is constantly happening is a core is trying to run at the maximum 24 multiplier but any background activity while you are benching kicks the multiplier down to a lower value. It might drop all the way down to 21 when two cores are active or it might drop only to 23 or 22. The multiplier on these CPUs will constantly be cycling like this, hundreds of times a second, based on load. CPU-Z rounds the multiplier off which may or may not be 100% accurate.
i7 Turbo is based on the Intel Turbo White Paper. It compares two high performance timers within the CPU to accurately calculate the average multiplier during an interval. This is the method that Intel recommends for CPUs that support Intel Dynamic Acceleration like some of the Core 2 mobile chips or Intel Turbo Boost which Core i9/i7/i5/i3 CPUs use.
Enabling C-States or C3/C6 allows the cores that are not doing the work to enter the sleep state and become inactive. The maximum multiplier available is based on how many active cores you have. The fewer cores active, the more bins of turbo boost will be available to you.
Model Specific Register (MSR) 0x1AD contains information about how many bins of turbo boost are available. My tool will show the specs for when 4, 3, 2 and 1 core is active. The 4 numbers will be side by side and are in hexadecimal format.
http://www.fileden.com/files/2008/3/3/1794507/MSR1AD.zip
When 4 cores are active, we know the maximum is 21 and when 1 core is active, we know the maximum is 24. I'm just not sure about what the two center values are for this CPU.
24 decimal translates to 18 in hex and 21 decimal translates to 15 so you should see something like:
15 __ __ 18
What do the two center numbers show?
This tool also works on the previous Core i7 CPUs.
Edit: Next time you are running wPrime, include Core Temp and i7 Turbo. The reported temperature looks like the two center cores are doing most of the work. When playing around you can also go into the Task Manager and right click on a task and use Set Affinity... to lock it to a particular core or cores. Hyper PI is another good testing utility that lets you run 1 to 4 instances of SuperPI. When running a single thread of SuperPI, it automatically locks it to one core.
Your screen shot shows that you are running a single threaded task which is being mostly shared between the two center cores. The two outside cores are in charge of running any background tasks while this is going on.
On a Core i5 750, you will get a 24 multiplier but you only get this when 1 core is active. The two center cores are taking turns as the active core while the two outside cores are spending most of their time asleep.
I don't have the official specs yet but I'll post a utility that you can use to confirm your CPU's capabilities in a moment.
As soon as 2 cores are active, your CPU will no longer be able to use the 24X multiplier. When all 4 cores are active, your maximum multiplier is 21. The Load Filter setting in i7 Turbo limits the data going into the Min and Max boxes. In your screen shot you have this set to 95% (the default) so it is recording the min and max multiplier only when your load is over 95%. If you change this filter to 0%, then all data will be considered for the Min and Max statistics. That's why it is only showing 21.000 because at full load, greater than 95%, that's all this CPU can do.
The 23.733 and 23.829 values for the two center cores are a very accurate average of the multipliers for those two cores during the previous 1 second interval. What is constantly happening is a core is trying to run at the maximum 24 multiplier but any background activity while you are benching kicks the multiplier down to a lower value. It might drop all the way down to 21 when two cores are active or it might drop only to 23 or 22. The multiplier on these CPUs will constantly be cycling like this, hundreds of times a second, based on load. CPU-Z rounds the multiplier off which may or may not be 100% accurate.
i7 Turbo is based on the Intel Turbo White Paper. It compares two high performance timers within the CPU to accurately calculate the average multiplier during an interval. This is the method that Intel recommends for CPUs that support Intel Dynamic Acceleration like some of the Core 2 mobile chips or Intel Turbo Boost which Core i9/i7/i5/i3 CPUs use.
Enabling C-States or C3/C6 allows the cores that are not doing the work to enter the sleep state and become inactive. The maximum multiplier available is based on how many active cores you have. The fewer cores active, the more bins of turbo boost will be available to you.
Model Specific Register (MSR) 0x1AD contains information about how many bins of turbo boost are available. My tool will show the specs for when 4, 3, 2 and 1 core is active. The 4 numbers will be side by side and are in hexadecimal format.
http://www.fileden.com/files/2008/3/3/1794507/MSR1AD.zip
When 4 cores are active, we know the maximum is 21 and when 1 core is active, we know the maximum is 24. I'm just not sure about what the two center values are for this CPU.
24 decimal translates to 18 in hex and 21 decimal translates to 15 so you should see something like:
15 __ __ 18
What do the two center numbers show?
This tool also works on the previous Core i7 CPUs.
Edit: Next time you are running wPrime, include Core Temp and i7 Turbo. The reported temperature looks like the two center cores are doing most of the work. When playing around you can also go into the Task Manager and right click on a task and use Set Affinity... to lock it to a particular core or cores. Hyper PI is another good testing utility that lets you run 1 to 4 instances of SuperPI. When running a single thread of SuperPI, it automatically locks it to one core.
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