Limp, If I were you I would invest in a better water cooling setup. Dump that gigabyte liquid cooling-GH-WIU02 and go with something like the Swiftech H20-220. I know it will cost you some more cashola but it will pay dividens in the long run. Those Quads need some good cooling if they are to be over clocked.
http://www.newegg.com/Product/Product.aspx?Item=N82E16835108076
Motherboard: EVGA T1 680i
CPU: E6600 L646G494 @ 3.7Ghz. 1:1 Ratio Linked & Synced Voltage 1.44 Load Temp 45c
Idle Temp. 25c
SPP:1.45volts, MCP: 1.50volts
Memory: Mushkin PC2 8000 2gig's 4-5-4-11, 2T Voltage 2.1
Swiftech Water Cooling H20-220
Video: One EVGA 8800GTS 320MB
Power Supply: Silverstone 750W
OS: XP Pro
Soon to be a Q6600