Get the I860 over the 920
860 - faster in games
- runs cooler
Hyperthreading hurts games and makes the cpu run hotter.
The memory controller on the 750 and 860 are on chip so latency is better than i920 x58.
The memory bandwidth of 21 vs 25 gigs/sec is not worth bickering. Games are not needing 10/gsec so the extra is overkill in terms of gaming, its more of a mental what if or bragging rights having trichannel mem.
They are all good chips and all will perform so closely that you won't be able to tell in game.
Turn off HT if your gaming it will only help.http://www.bit-tech.net/hardware/cpus/2009/09/08/intel-lynnfield-details-and-architecture/1
Some info on the chips in more detail.
I'm getting a 920 because its prebuilt and done though business account.
If I were building my own I'd use the 860 because its faster in games.