Well if u're a non-OC guy, then I suggest OC, and I'll push my point further:
Default:
Core - 750MHz
Memory - 800MHz
Memory is rated to run at 1GHz(hynix, rated) so u can set the memory at 1GHz w/o any further thinking because it was MADE TO RUN at that speed.
About the core, you can increase by 50-100MHz(both will be very easy, becuz the core goes to 971MHz on the stock cooling, and i'm not talking about amd's premium cooler here).
So u see, even if u rn't an OC guy, I suggest u be one, for the sheer performane gain(beats the GTS 250 at afore-mentioned speeds).
Else, u can still buy he card and not OC, ur choice.