video card for 2560x1440

[Vu Pham]

Hi all,

I just got a 2560x1440 monitor. It works fine with my notebook, in the 
meaning that the texts/pictures are clear and easy to read at the 
resolution 2560x1440.
When I tried my desktop with that monitor, its video card ( some cheap 
video card ) supports that resolution, but the screen quality is very 
bad. Thinking that the card might be too old, I ordered a new ( but 
still cheap ) video card that also supports that resolution, and I still 
have the same problem. This happens with both HDMI and DVI connectors on 
both video cards.

So what criteria should the video card need to have to support a good 
qualty 2560x1440 ?

Thanks,
Vu