200 Mhz difference doesn't matter. Has anyone looked at the stats on Intels website for the 920 vs 860?
http://www.intel.com/products/processor/corei7/specifications.htm
Bus speed is 4.8 Gt/s for a 920 and 2.5 Gt/s for a 860. Even if an 860 is a little faster if the bottleneck is smaller BY HALF, then you push less data through. Its pretty simple! Turbo boost and over clocking don't mean anything again if you can only push through HALF the data of a 920's Bus. I would also agree with the earlier post of 920 = 24 GB of RAM and 860 = 16GB, if you want a power house for video encoding, gaming, or apps 920 wins again. Bus speed is key! Overclock your heart out of a 860 if you can't match the bandwidth (i.e. Bus Speed) of a 920 with triple channel memory then you can't come close to the power. Why would anyone think a 860 is faster?
Misconception, and I'm hoping my email is going to get that fixed. 🙁
QPI is the connection between CPU and northbridge, and DMI between northbridge and southbridge. On 920, the 4.8GT/s is between the 920 and the X58 and there is a 2.5GT/s DMI port between X58 and the southbridge. On 860, the northbridge is on the CPU silicon (as is the QPI), and the DMI is between the CPU and the PCH (southbridge). There's no penalty on the 860 due to DMI vs QPI.
Bus speed is really a meaningless concept from that perspective, and other than "tradition" I don't know why it's specified in those terms on the website.