What's the stock core and memory? 400 core and 300 memory? If so, that's decent. Memory seems to not overclock as good as the core, just like mine. Just make sure you have good cooling.
I can't get mine too high (yet) because I haven't installed my VGA Silencer. And the fact my FSB is 220, causes me not to be able to OC my card too high (over 450 core) without getting booted out of graphic-intensive games.