For mining scrypt-based coins with a gpu, the hash rates are largely independent of the cpu and ram. I have the same card (270x) running on an old Core 2 Duo processor I bought years ago and it generally gets around 475kh/s runs around 65C (1120 Core, 1500 Mem).

If your temps are that low, it wouldn't hurt increasing the core clock a bit and seeing if you can push it a bit more. Just increase like 5MHz at a time and observe the hash rate. If the computer becomes unstable, just back it up and find the sweet spot. If you want more overclocking info, check out the gaming forums for overclocking (just google overclocking forums).

I'm not sure if its the same with your card, but hashes drop fast if I go over 1500MHz on the memory (e.g. 1501MHz). Maybe it'll work better for you, but just be sure to adjust the the two clocks independently in case one gives you a problem.

It sound like you just have an excellent cooling system on that card, might as well take advantage of it! Good luck!