RO2 My GPU died, please help me to choose new GPU only for Red Orchestra 2! :)

Hi



My old GPU died, and I need new one.

Because my PC is not young, so I want to buy the fastest GPU for my current setup.

I don't know that I should buy GTX or Radeon.



My current setup.



CPU: Intel Core 2 Quad Q9550

RAM: OCZ REAPER DDR2 4Gb 2x2Gb 1066MHz

LCD: Resolution 1680x1050, soon maybe 1920 x 1080



So far I have chosen:

GTX 560 TI 2 GB

RADEON HD 7870 2GB



I do not play other games, so the GPU will be only for Red Orchestra 2!

Please help me to come back on battlefield!



:IS2: you so much for your help!



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I need one more thing, I can buy parts from USA or UK.

So if you are USA or UK citizen could you advise me the best places to buy USED but also NEW PC parts, please!