UPDATED: Overclocking--Overspeed Protection, Explained
Overclocking Made Different
Overclocking is very different on the Core i7. Unlike the Core 2 or Pentium D processors, the Core i7 CPU can monitor the current it draws as well as its power consumption—if it exceeds a certain level, the processor automatically reduces its clock speed. Intel calls this feature "Overspeed Protection." The limits hard-wired into the core are 100 A and 130 watts. Only the Extreme Edition allows the user to change these values at will, effectively circumventing the protection mechanism altogether.
Chris Angelini: The rest of this page has been re-written to reflect our secondary overclocking efforts using a wider range of hardware and benchmarks to confirm the results.
Intel says that Overspeed Protection exists as a means of keeping notebooks, servers, etc. from encountering stability issues due to overzealous tweaking. However, the company acknowledges its contingent of overclocking enthusiasts, and provides a BIOS switch able to work around the feature. As discussed in our recent Editor’s Corner, this is called CPU VR Current Limit Override in the DX58SO’s BIOS.
If you’re running an i7 920 or 940, enabling this software-based workaround will let you smoke right past the 100A/130W limits, as we did in that first update.
After running a handful of benchmarks to confirm that our Core i7 920 was in fact operating at 3.8 GHz on ASUS’ Rampage II Extreme, we can comfortably say this issue has been addressed and, if anything, is a platform problem. There’s no way to guarantee that all X58-based motherboards will include a bypass to Overspeed Protection, but it’s a fair bet that if Intel—perhaps the most conservative motherboard vendor around—is willing to enable it, so too will the third-party board vendors.
If you have any other questions about Intel’s artificial overclocking ceiling, again, refer back to the Editor’s Corner story, where we demonstrate the effects of getting hit by Overspeed Protection and getting past it.
