Incorrect multiplyer on CPU-Z?

[3DChipset]

I've noticed that the multiplyer for the i920 is 20 right? So why are all the CPU-Z screenshots show a 21 for the multiplyer? Because 20x133 = 2660 and obviously 21x133 = 2793. A bug?

 

[Nanoha]

Turbo Boost increases multiplier by 1. It boosts processes that use only one thread as determined internally by the processor when certain requirements are met. I don't think there is a way to force it to be always on.

It appears as 21 in CPU-Z but really is only 20 under normal conditions for most processes.

 

[3DChipset]

Ah................ Thanks for the clarification. I was curious about that.

 

[Zero82z]

I don't think there is a way to force it to be always on.

I believe some motherboards can do that.

 

[ilkhan]

You don't want it always on, it causes more heat and power draw (opposite of speedstep) within the 130W power envelope.
But its useful when not using all 4 cores.

 

[Nanoha]

Aha, I see. Thanks for the correction.

 

[DragonQ]

Actually the 21x multiplier can be applied to all cores. It's the 22x multiplier that can only be applied to a single core.

 

[unclewebb]

You don't want it always on,

Why not?

If you are not overclocking the BCLK, you should have EIST, C1 and C3/C6 enabled in the bios. With Windows Vista you should also have your Control Panel -> Power Options -> Minimum processor state set to a low number like 5%. It won't actually go down that low but this will enable it to go as low as possible at idle.

With all these items set correctly, you'll get a multiplier of 12 at idle and your core voltage will drop down so you will save power and any time you are running a single threaded app your multiplier will try to jump up to 22 as much as possible to maximize performance. Some boards will let it run continuously at 22X when running a single threaded app while other boards will constantly cycle it between 21 and 22. It depends on the board.

As soon as you start overclocking the BCLK, how your motherboard handles the multipliers can completely change. Surprisingly, the Intel motherboard is one of the better boards and follows the Intel design spec correctly when not overclocking.

Every board and bios version is unique so it's always wise to do your own testing. i7 Turbo V8 will show you what multiplier you're actually getting on each thread. Here's the [H]ard thread that tells you all about it:

http://www.hardforum.com/showthread.php?t=1417780

 

[slavearm]

Wow... thats a great link. Thanks Unclewebb.