which one is better?

[Barfo]

I have a Dell 1907FP monitor and a 7900GT graphics card, which setting will yield better image quality?

and will enabling the graphics card scaling cost me some performance in 3d games?

 

[coolpurplefan]

I believe native resolution is usually better. And, you can check out xbitlabs benches for performance.

EDIT: I got one here. Just click on the names of the games and scroll down to see how the scaling works.
http://www.xbitlabs.com/articl...lay/geforce7950gt.html

 

[xtknight]

Depends on the video card and depends on the monitor. It really does. Of course, native is always best.

I don't believe that using graphics card scaling will sacrifice your 3D performance at all. It seems as though this exists on a different part of the chip. You could run some benchmarks and let us know.