MY E6300 can achieve at peak:
60FPS @1240*768 in oblivion
60FPS @1280 *1024 in FEAR
that is with XP, 2Gigs of Ram and a single 7300GT
Buy the best CPU in the C2D range you can afford, it the best idea.
You are not stupid so dont go for the AMD, that is old news, you wouldnt buy a pentium 3 would you, its just from a different manufacture.
LGA775 also has alot of live left in it, at least 1 and a half years, and even when it is replace (unlike AMD) they keep old sockets going for ages with new CPUs and chipsets, such as socket 468. AM2 is going to be replaced soon, so keep your money and go with intel.
you may also want to CONSIDER vista, for direct X 10 and X64 bit operations, you can always send it back if you dont like it saying your pc isnt powerful enough, you could also dual boot with XP or Linux with vista for direct X10 using XOSL
Dont forget to use DDR2 at least 1 (but realalistically 2gigs for games and 64 bit operation) of RAM
What card did you have before the GTS that you are comparing it to? Paired with an FX-55, the 8800GTS is very good, but not kicking butt compared to the X1950XT I used before it. I'd think if I had an A64 3000+ instead, I may hardly see a difference in some games.
I'd OC that CPU for starters. If you haven't noticed, it's hard finding S939 X2's in stock right now. And if you do find them, they are alot more expensive than AM2.
If you already have an AMD 3000+ is that on a Socket 939 or AM2? Why not just upgrade to a dual core CPU for that platform?
No, your better off with a e6300 or an e6400, althlons are dead, an e6300 can render better than a fx62, go witha 64 or 63 it doesnt need to be much more powerful unless your really serious or rich.
get some ddr2 while your at it
I just have to jump in here. If your performance is really fine now, why would you want to go to all the trouble of buying a complete new system, all the reloading and reformating, not mention the expense when an X2 is a drop in cheap upgrade? And you sure won't notice THAT much of a jump in frame rates with Core Duos over say a 4600X2. You will spend much cash for very little noticable improvement over the X2 for what you are doing.
You could also just overclock the 3000+ you have now.
Now if you were complaining that you are just not happy with your system, too slow, doesn't get the job done, ready to upgrade the whole stinking thing, then we would talk e6400.
Dual core cpu like E6300, X3 3800, 805 and etc should be good enough with the 8800GTS 320Mb. At 1280x1024, 8800GTS 320mb can even outperform 8800GTS 640Mb with the same hardwares. But if that old montherboard supports dual core X2 then you should go for that and save money.
when buying PC components, you just have to buy the best you can afford without thinking about it to much, if you can afford the e6300 (which i happily recommend) and a new motherboard then go for it, if you cant then get another athlon - but if youy can dont get another athlon movw with the times.
Just get an E4300 and the GA-965P-S3, should be less than 300$ total and a very nice upgrade. If you overclock that processor it can be insanely fast, but even at stock speeds it would a lot better than what you have. If you ever play Supreme Commander you'll be happy you didn't stick with the A64 3000+, and that might be true of most of the upcoming big DX10 titles.