buggerseems I can't find this setting for pair up, all i'm getting is the usual 'turn off modules' option. even flashed the bios [I was running a hideously out of date version] but no change [although ironically the bios screen looks and performs better]
edit: it's the board, the crosshair 5 does it, i'm on a sabertooth and realising one of the reasons the ch5 is more expensive.....
on a brighter note, found this:
http://www.xtremesystems.org/forums...ew-(4)-!exclusive!-Excuse-for-1-Threaded-Perf
seems that it is indeed better if you aren't going to be using all 8 cores.
Thats an interesting read but i'm not sure he proved what he appears to have set out to try.
I'm struggling to understand whats going on in that thread.
He ran a lot of test, all of them multithreaded and in that what he did prove was that in multithreaded apps locking the modules into 1 core significantly reduced multithreaded performance.
He hasn't run a single 1 thread application to actually test for single threaded performance improvements

Look at his slides, every single one has 2CU/4C and 4CU/4C slower than 4CU/8C and often with 2 modules turned off altogether its better than all 4 modules locked into 4 cores