Shuttle and 6800gt

welll I posted here about a month and half ago about my shuttle and buying a 6800gt and things arent going exactly as planned. So here is the background info again, the main game I play is raven shield and I currently own the shuttle special anniversary edition which has a 220w power supply, which I think may be my problem. I currently have an EVGA 6800gt, 2.8ghz p4/HT, 1gig PC3200 Ram, SoundBlaster Audigy2 ZS, 160gig HD and lite-on DVD burner. The card runs fine (as far as no crashes) but I experience a lot of fps lag/drops in game which I don’t remember experiencing with my 9600pro.Vsync has been off in both cases and I can only seem to run at stable fps with 800x600 on GT while 1024x768 worked fine on the 9600pro. So far under clocking it has helped but still drops to 50fps in some areas and 20 in others while peaking at 180 or so. My latest 3dmark03 score 7951, this should be alot higher right?? . Would it be smart to upgrade to a new case with a higher psu, I have been looking at this.

(http://www.newegg.com/Product/Produ...N82E16811133156)

And just buying a new mobo for around 60$?

Would I see a real boost in the fps and performance of the card?

If you think it may be a temperature related issue (well, i do) take the case side off and run a regular fan over it to cool the air.

Play the game, and if it's better, there's your answer.

the card has a built in temp it usually stays around 70-80 degrees while playing.

I was also given the option of buying a 300w psu for my shuttle for about 70$ on newegg, so do take that into consideration also.

Well it certainly could be a PSU issue, but i'd try to solve it for free before spending cash.
That said, i have only heard good things about the updated 250W and 300W silent PSU's from shuttle, and it COULD be that the fans on them would also help shift a little extra air in your case, but that's only a guess.

Take the case side off first.