Core 2 DUO build mid-range

I got a core 2 duo setup as agift an XFX motherboard an 2.9 GHZ processor. It was a gift to me I paid 0 dollars so that automatically makes it good enough for me. My gift giver skimped on a power supply f course but I can fix hat easily because it's only a micro atx mobo no possibility for any poerful gfx card either on windows xp until I get windows 7 in few. I want some suggestions on graphics cards, specifically radeon hd 5700 series. From someone that ACTUALLY HAS EXPERIENCE WITH IT I want to know how that card would do with a C2d bottlenecks? maybe some game performance or benchmarks. I'm excited to because I want to overclock a core 2 after seeing all the headroom there is. So maybe if someone has any cooling reccomendations for this platform, I was thinking core conatact freezer? also FROM SOMEONE WHO HAS ACTUALLY DONE IT some overclocking advice on a ati 5700 series and core 2 processors. For the record I'm an avid modder, and tweaker but I'm concerned because this is a platform I haven't done before I normally work with amd and when I use intel it normally invol ves 4GHZ pentium4's. SO anyone's contributions would be apreciated.

No problem at all using a mATX mb .So long as it has a pci-e x16 slot the mb wont be an issue .

I have an e7300 that clocked so easily to 3.33 GHz by setting FSB to 333MHz [ 1333 ], instead of the original 266MHz . I also lowered the voltage marginally. It has a scythe ninja cooler on it and runs very very cool . Theres a lot more head room but its fast enough at that speed so Im not concerned about getting it clocked higher . Esp as that would add heat and noise .

Follow the OC guidelines in the cpu section of these boards .

Install the ATI CCC and over clock from there . Watch your temperatures but the 5770/5750 run pretty cool anyway

Where did you read the duo is a pent D?