you can overclock the Graphics card, not not very far.. and only the Core Clock, the Shaders, and the Memory.. You can use eVGA precision. but I'd recommend not going anywhere over about 100 on the Core Clock, and not much more on the rest.
Example, the Ultra. is 612 MHz Core Clock and like 1080 on Memory, and shaders if I remember right are around 1600. I could be wrong on shaders. I know the Ultra doesn't overclock very far. so I recommend getting eVGA Precision. ALWAYS watch temps and do something like this.
666 Mhz Core, or 670 Mhz Core. But no More, or will be to hot.
1120 on the RAM.. and on the shaders I'd say raise it by around 50..
Youy may THINK you can go higher than this, but temps will be very hot, and games will crash. and it's not safe as thats an old card on a 90mn tech.. So I'd recommend not going any higher than what I've said above.
Also, the 780i SLI.. is that the SLI FTW version, or only the SLI model?
Also the Q9300 doesn't have a very good Multiplier. I'd say push it to 3.0 ghz and stop there, as the cooling isn't very good either. I'd get a better Cooler if you wanna push that Quad anywhere above 3.0 Ghz.
Also, be very careful with overclocking Either of these, in order to OC the CPU. you need Core Temp for temp monitoring. and CPU-Z for checking the overclocks. get either of those at any download place. just google it.
if you don't know how to overclock the CPU.. be careful, and ask questions first.. don't just try something. as you could damage something. So just be careful. I'd hate to have something happen to that lovely Rig.