Hi.
Native support for up to 4 simultaneous displays
Up to 6 displays supported with DisplayPort 1.2 Multi-Stream Transport
Independent resolutions, refresh rates, color controls, and video overlays
Display grouping
Combine multiple displays to behave like a single large display
Here is a link to your Hd6970 specifications:
http://www.amd.com/us/products/desktop/graphics/amd-radeon-hd-6000/hd-6970/Pages/amd-radeon-hd-6970-overview.aspx#2
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About the watercooling...
1 -It is dangerous to make it if you aren't an expert.
2 - It isn't usefull if you are a normal gamer, You need watercooling if you Overclock your system really much... like if you have a Processor of 3.16ghz and you Overclock it to 4.3ghz
You need to use 2 Dvi-d and 1 Hdmi,
I always used air cooling and all is Ok :)