I'm running 1920x1080 in most games. I mostly play TF2. Is this game GPU intensive?
The mobo you suggested looks like I can get another 9800GTX and connect via SLI. Would this be worthwhile?
No the 9800GTX is too old for SLI. Its big, power hungry, hot and doesnt run DX11 and other newer tecnologies. You can get equivalent power for less in a newer card today that would run cool and quiet. The PSU and cooling needed for that setup isnt worth it.