I've noticed when I extend the desktop to both screens I have some "flickering" on the second 17 inch monitor. Almost like its trying to adjust itself to something automatically. It only flickers when I scroll the mouse wheel up and down a page or move a window around, etc. Seems to happen when one screen has a browser at full screen and something might be leaking over to the other screen, not sure if I can explain it better than that.
If you plug the monitors in separately is it OK? It's probably a refresh issue or resolution, make sure its set to 1920x1080@60hz or whatever. Although i wouldnt recommend pairing a 17" with a 24" for Eyefinity.
ALSO, I am assuming this videocard with two monitors on it may take a performance hit if I use it while gaming? For example have the 24 inch be the gamer monitor and have the 17 inch showing the desktop with a browser window, or teamspeak on it?
Yes youll take a huge hit performance wise, both from the GPU (rendering 2 screens) and the CPU (compute for 2 screens worth of stuff) - but ifyoure talking about 1 screen for gaming, and the other for desktop work - then no, with a decent enough video card/cpu you wont notice a diffrence. The video card barely breaks a sweat doing desktop stuff, and if you have a 4 core cpu - all the desktop work will be on other threads, most games dont take advantage of more than 2 cpus. A 5870 and a cpu newer than 4 years should be fine for what youre trying to do.