Here are my results

1 Video Card 1 Monitor
4xWoW Stacked
Frames: 90-100fps
CPU Usage: 65-70%

1 Video Card 2 Monitors [Duel View]
2xWoW Stacker per Monitor
Frames: 45-50fps
CPU Usage: 50-60%

1 Video Cards 2 Monitors [Horizional Span]
2xWoW Stacker per Monitor
Frames: 80-90fps
CPU Usage: 55-65%

2 Video Cards 3 Monitors
2xWow Monitor 1, 1xWow Monitor 2,3
Frames: 35-40fps
CPU Usage: 40-45%

2 Video Cards 4 Monitors
1 WoW Per Monitor
Frames: 15-25fps
CPU Usage: 35-45%

CPU usage goes down but Im not really keen on clocking my machine, the weather here is often around 40-45degrees (104-113 fahrenheit) and id be worried to fry something.
Im going to try setting affinity and playing around with resolutions and see if it makes a difference.
Thanks