on any given day my computer rates a lovely 5.0 on the vista rating thing with my aero graphics rating at 5.9 and my gaming rating at 5.8 on an nvidia 7900gs 256 mb can play any game with medium settings, gears of war, crysis, farcry2 you name it so i figured a newer card with direct x 10 would allow for better gaming so i bought n 8400 gs just a little step up i figured with direct x 10 512mb card toobut upon putting it in my vista rating drops all the way down to 3.3! and i cant play most of my games on the lowest settings i went to nvidias webstie and dled the drivers and at a glance it appears to be the same drivers that i use for my 7900 so whats going on here is that card really that bad or did i do something wrong?!?!

Yes, you effectively downgraded your graphics cards.
James

Model numbers mean little these days. These days it's all about card architecture and under the hood performance and all that stuff.

Kind of like saying you have a car registered September 2004. You go and buy a car with a September 2007 registration. Doesn't mean it's any better, you're still likely to hit something with it.