Apple's new iMacs come with a 2.4 Ghz Core 2 Duo or a 2.8 Ghz Core 2 Extreme. Beyond the 0.4Ghz speed difference, is there any other differences? I.e. What makes an Extreme, Extreme? Is it just marketing for the current high end chip?
"Do the Right Thing. It will gratify some people and astound the rest." - Mark Twain
This is not exactly for the 2.4 / 2.8 GHz processors, and the article is dated " July 14th, 2006" but I guess this is still accurate:
Core 2 Extreme vs. Core 2 Duo
Previously Intel had differentiated its "Extreme" line of processors by giving them larger caches, a faster FSB, Hyper Threading support, and/or higher clock speeds. With the Core 2 processor family, the Extreme version gets a higher clock speed (2.93GHz vs. 2.66GHz) and this time around it also gets an unlocked multiplier. Intel officially describes this feature as the following:
Core 2 Extreme is not truly "unlocked". Officially (per the BIOS Writers Guide), it is "a frequency limited processor with additional support for ratio overrides higher than the maximum Intel-tested bus-to-core ratio." Currently, that max tested ratio is 11:1 (aka 2.93G @ 1066 FSB). The min ratio is 6:1. However, do note that the Core 2 Extreme will boot at 2.93G unlike prior generation XE processors which booted to the lowest possible ratio and had to be "cranked up" to the performance ratio.
In other words, you can adjust the clock multiplier higher or lower than 11.0x, which hasn't been possible on a retail Intel chip for several years. By shipping the Core 2 Extreme unlocked, Intel has taken yet another page from AMD's Guide to Processor Success. Unfortunately for AMD, this wasn't the only page Intel took.