I have Gigabyte GTX 460 SOC - it runs at:
GPU 900MHz, 950 is the limit I understand
shader 1780Mhz
memory 1050MHz
never goes over 60c, fan usually stays around the default 40% (near silent) but can go up by a couple of percent - can play all games inc BF3 @ ultra settings, 1920x1080 (approx 40fps)
BC2 checked recently averaged around 60fps, highest possible settings, 1920x1080, 32xCSAA, 16xAF etc etc
it's a wonderful card that was underpriced when it hit market - it's still roughly the same price now - approx 1 year later
If I had the cash I'd go for some of these, for me the GTX 460 / 560 / 560ti need 2 fans, GTX 570 2/3 fans...
Gigabyte GeForce GTX 560 Ti SOC (rev 2.0)
N560GTX-Ti Twin Frozr II/OC
or
Gigabyte GeForce GTX 570 Super Overclock (out performs reference GTX 580)
MSI GeForce GTX 570 OC Twin FrozR III (performance similar to Gigabyte I would imagine)
all can be SLI at later date if need be
let us know how you get on
cheers
chaz