er hem, didnt mean any personal attacks,burleyman recommended a system upgrade, which is most likely needed, unfortunatly, you mentioned your running a PCI video card, which, makes me assume that you lack an AGP slot, even a PCIe slot. that being the case, a new system would be best, becuase your not going to get any more performance out of PCI outside of the FX5500, thats the end of the PCI line.
only solution to that, new mobo, which means most likely a new CPU, which means a new type of ram....see where that line travels.
There is no way to easily answer your question either, as to whom gives the most comprehensive performance. ATi and nVidia are the two companies that offer a product worth purchasing, and theyre both really on the same edge anymore, it levels on price/performance, atm, ATi delivers the better high end cards, whereas nVidia delivers the extremist cards, and the low to midrange cards, those are their strong suits.
As to Differnt socket types
PCI - Dead, ancient, slowly being phased out, best video card your going to find in that interface, is like I mentioned previoulsy, the FX 5500 from nVidia
AGP - Also dead, well, its being slowly killed off, best video card youll find for this interface is the 7800GS from nVidia, but it caries a huge price tag.
PCIe - This is the new standard, currently the fastes card is nVidias 7950 series, the fastest reasonably priced card is the ATi 1900 series, even the 1800 series, the best midrange card, the 7600GT, the 7900GT is priced for high end, bt doesnt hold much of a candle to the 1800 series, nor does the 7900GTX hold up well to the 1900 series from ATi.
Low end, 7300 is a solid performer.
IF you lack anything outside of PCI, just upgrade to a PCIe based board, otherwise youll winf up in the same hole I believe you are in now, a very dead end.
Hope that was more...helpful for you
and I only upgrade yearly, minor upgrades maybe 4-6months apart, I dont buy a new PC on a more frequesnt basis then 2-3 years
my last PC, i bought an opty becuase it was cheaper then buting an X2, overclocked it to 2.5ghz which landed it right between at the time, the two most expensive chips that AMD offered, the X2 4800+, and the FX60, one being 850USD, the other 1100, i payed 315 for my opty, so I dont blow a lot of money either, my next CPU upgrade wont occur for another 2-3 years, about the time I ask the same question your asking.