I thought all Core i7 920 processors had a locked multiplier?
Well i got this D0 stepping 920 last week and in the bios it says its unlocked, and i have been able to boot into windows with the multiplier at 20, 18, and 15. It gives multiplier options from 12 to 21. So is the CPU actually unlocked or is my motherboard doing something special to allow it to do this?
I have the new MSI X58m mATX motherboard.
i7 920 D0 Unlocked?
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I'm fairly confident in what I am about to say, but fact-checking is always good :-/
The Core i7 920 does have a locked multiplier, but that does not mean that there is no multiplier control. Basically, the multiplier is locked upwards (meaning that it cannot go about 20x under normal circumstances). So although there is control over the multiplier, it stops at 20x (133 base clock x 20 = 2.66GHz)
The reason why it gives a setting of 21 is because the i7 systems have something called Turbo Boost, which allows the processor to detect when it has extra thermal overhead, and overclock the core(s) a little bit. This means that although your processor is rated for 2.66GHz, it can go higher if the conditions are right. The methods for determining what the max speed and under what conditions it will self-overclock are pretty complex.
The Core i7 920 does have a locked multiplier, but that does not mean that there is no multiplier control. Basically, the multiplier is locked upwards (meaning that it cannot go about 20x under normal circumstances). So although there is control over the multiplier, it stops at 20x (133 base clock x 20 = 2.66GHz)
The reason why it gives a setting of 21 is because the i7 systems have something called Turbo Boost, which allows the processor to detect when it has extra thermal overhead, and overclock the core(s) a little bit. This means that although your processor is rated for 2.66GHz, it can go higher if the conditions are right. The methods for determining what the max speed and under what conditions it will self-overclock are pretty complex.
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LodeHacker
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The link that LodeHacker...er...linked is talking about the QPI (Quick-Path Interconnect) portion of the Core i7. This has been unlocked in the sense that it can now run at the full 6.4GB/s, as opposed to what we thought was the maximum 4.8GB/s. This does not, however, increase the CPU core frequency. It is still nice, however, because it makes it possible to run faster memory and perhipherals.
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LodeHacker
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Actually I linked to that article for this small text portion:tehfire wrote:The link that LodeHacker...er...linked is talking about the QPI (Quick-Path Interconnect) portion of the Core i7. This has been unlocked in the sense that it can now run at the full 6.4GB/s, as opposed to what we thought was the maximum 4.8GB/s. This does not, however, increase the CPU core frequency. It is still nice, however, because it makes it possible to run faster memory and perhipherals.
* Locked multipliers so you cannot exceed their rated top speed (without overclocking the base clock).
* Locked Turbo Mode multipliers so you cannot make fine-grained adjustments to the Turbo Mode features.
* Have unlocked QPI speeds but are officially rated for 4.8GT/s.
* Have unlocked memory multipliers so you can select from 1066/1333/1600/1866 and up.