did you manually assign WoWs to your cores?
No. How is this possible? (remember: i use actually just a Dualcore).

are you running all those displays off a single machine? 3? out of curiosity, can you move windows between the monitors (ie: is it spanning)
Yes, as writen above, it`s a single machine. Due to the reason that i use Vista and Geforce 8 (DirectX 10) a Span-Mode is not anymore available (but even useless). Vista works directly like in Span, so yes, i can move all windows between the monitors.

try dropping the main to something like 1280x1024 (3.9MB/frame) or lower
I did, but works only 'smart' if all other windows are minimized.

how about dropping one of the monitors and running your support clones in a 2x2 maximizer grid?
Not 'the perfect' solution.. but would be an idea (if i could get maximizer work!).
i had also read something about multi monitors being slow on the non-main monitor. could this be effecting your rig?
Really? I try this! Question would be: What is the 'main' monitor? The first (physical) PCIe Card?

any guinea pigs willing to beta? if so, please send me a PM
Fore sure! PM sent !

i realized that i was assuming 24 bit color... many systems use 32 bit color. adjust accordingly to determine throughput
Tried it in all versions, even with 16 Bits and disabled Multisampling (no result).

So you think a Quadcore will solve my problem? It`s not affected by the grafik-card?

edit: Just checked it: Only one WoW instance takes 70% ! of CPU load (thats not normal, or?)