Yeah, I mean even the 9800 GT2 only has a clock speed of 600 MHZ and this guy wants 700 MHZ on an 8400??
Seriously, don't buy a cheap GPU and say your going to overclock it. Overclocking is better performed on high-end cards that can already cool their selves. Many smaller cards don't even have fans.
Buy an 8800 GTS 320mb, they are only 140 bucks on NewEgg.com.
And I recommend FPSC X9 over X10. More media, and mods that make it superior. If you are really serious about making games, checkout Leadwerks on the TGC store.