Need Advice on HD 6850 vs. 6770 crossfire

[Blorp Kola]

Hey guys I was just wondering would a 6850 be better at £120 or crossfired 6770 (2 for £200). What would give better performance to price ratio. The sorts of games played will be Skyrim, Guild wars 2, Deus Ex Human Revolution etc.
Will be playing on a 1920x1080p monitor with high graphics.
I am planning this for a new build with a phenom II x4 840.
If I do go for the crossfire setup I will need a crossfire motherboard obviously and a more powerful power supply (I assume). If the 6770 setup is best then please suggest motherboards and PSU's. If the 6850 will be better then I already know what I am going to get mobo and PSU wise.
Preferable available on ebuyer.com
Budget for mobo PSU and GPU/GPU's is £300
Thanks in advance for any advice

 

[azeem40]

http://www.tomshardware.com/charts/2011-gaming-graphics-charts/3DMark11-Gamer,2659.html

 

[simon12]

Why are you comparing those 2 x 6770 is more expensive than a 6950. I suggest get either a 6950 and leave it at that or get a 6850 and buy a second one when they go under £100

 

[Blorp Kola]

Ok thanks for your advice, what sort of PSU and mobo should I be looking at for a 6850 crossfire.

 

[esrever]

I'd stay away from low end crossfire as it is not always reliable. Get the best single GPU you can and then get crossfire later once prices go down. This way you aren't severely limited if a game just doesn't work well with crossfire.

 

[simon12]

This is the cheapest
PSU I would use for 2 x 6850s http://www.ebuyer.com/241554-xfx-pro-650w-core-edition-psu-single-rail-9x-sata-4x-p1-650s-ukb9 £67
I can't find any cheap AM3 motherboards I would recommend for crossfire but this is the best I can do http://www.aria.co.uk/Products/Components/Motherboards/AMD+AM3%2B+%28900+Chipset%29/Asrock+EXTREME3+990FX+%28Socket+AM3%2B%29+DDR3+PCI-Express+ATX+Motherboard?productId=46633 £92
= £159 leaving £161 for GPU
6850 for £111 http://www.ebuyer.com/284386-his-hd-6850-1gb-gddr5-dual-dvi-hdmi-displayport-pci-e-graphics-card-h685fn1gd
6870 for £128 http://www.ebuyer.com/279585-xfx-hd-6870-900mhz-1gb-gddr5-dual-dvi-dual-mini-displayport-hdmi-hd-687a-zhfc
I think you would be better with an intel build around an i3 2100 in terms or price performance.