Should I expect better on this system?

Recently installed a new geforce 9800gtx (overclocked version) (512 megs)and power supply (rocketfish 550 watt) on this new pre built hp tower, model number is... "a6700y", cpu is phenom 9150e 1.8ghz, ram 4 gig, hd 500gb, vista 64 bit.
I don't know much about the motherboard, but it's most likely lower end.
still feel like I should be getting more out of this system. common fps in most game settings high or maxed out is between 35-60 occasionally jumping up to a stable 70-80 in much less graphic extensive eviroments.I installed the video card first, and didn't see a performance difference between the new and the old generic 350watt psu. So I'm thinking it might have to do with the processor or motherboard. Any suggestions?

Yes but it's fair to say that a higher voltage psu being installed could have helped the card out, maybe not significantly. the minimum wattage for the 9800gtx is 450 watts, the generic was 350. And I need to find out the maximum wattage the motherboard supports for the cpu, and maybe I'll consider upgrading if it's worth it.

No the card either has sufficient voltage to work or it does not. Also that Rocketfish/Best Buy brand PSU is garbage. It is a 550w PEAK not continuous. Motherboard is likely to be a typical "the cheapest we could get" mass market brand and that processor as stated above is WEAK. I am kinda surprised you are getting the FPS you are.

you're right the psu is 500watt continuous 500 watt peak. I'm not entirely sure but the motherboard might be able to support a new 95 watt cpu. If I could get my hands on a better motherboard and cpu, I would just rebuild the pc.