[list]
[*]Is there really such a big difference regarding the need for performance between 1920x1080 and 1920x1200 ? Of course, I'd rather stay with my already existent 28" TFT (1920x1200) and buy two further screens than sell the one 28" and buy three new 26-27" screens with 1920x1080 ![/*:m]
[*]Do I need to upgrade my CPU as well ? Maybe it's the bottleneck in my system - I don't know whether it's necessary or not. I could upgrade to a Core2Quad Q8400 oder Q9400 which is supported by my board.[/*:m]
[*]If buying an ATI 5870 - which model/manufacturer should I take ?[/*:m][/list:u]
1 - Performance between 1920x1080 and 1920x1200 is almost identical. The 1080 resolution has about 10% less pixels, but it has a slightly larger FOV (thus rendering more objects on the screen). I stopped benchmarking both due to the negligible difference. Here are the last two articles with 1920x1080:
http://www.widescreengamingforum.com/wiki/Widescreen_and_Surround_Benchmarking_Suite
http://www.widescreengamingforum.com/wiki/WS_and_WTH_Benchmarking_(Core_i7_920_and_9800_GX2)
2 - Might be a good upgrade. Not totally sure. What's the cost on those CPUs.
3 - Everyone is basically making reference boards for the 5870 at this point. Choose a manufacturer you like, or that people have had good experience with. I can't say as all my boards are reference designs from ATI. The 2GB Eyefinity6 is coming soon. You might wait for that. Also, I think someone else is producing a 2GB 5870 board. If anything, I would try and get a card that has 2GB of VRAM per GPU.