CPU Bottleneck? Possible Upgrades?

Hello!

Recently my video card decided it wanted to stop working properly and is no longer under warranty, so I've got to replace it.

My current picks are the Radeon 38*0 or 4850, however it would be plugging into an older system.

ASUS A8N32-SLI Deluxe
AMD Athlon 64 X2 3800+ Manchester 2.0GHz Socket 939 Dual-Core Processor Model ADA3800BVBOX
CORSAIR XMS 2GB (2 x 1GB)DDR 400 (PC 3200) Dual Channel Kit Desktop Memory Model TWINX2048-3200C2PT

Have it all stuffed into a CM Stacker (Old model STC-01 or some such), with a OCZ GamerXStream 850w(replaced an old powerstream that failed in warranty). All plugged into a 20 inch wide screen (native 1680x1050 I think). The PC sees a lot of use, from general word processing/excel to massive gaming and I often watch dvd's and other videos on it.

Currently the only thing that requires a replacement is the video card, which no longer works. However my concern is given how dated my processor is that it is going to be a huge bottleneck for any card I can get.

So my question is, should I buy a even cheaper card (I do have a very limited budget) and upgrade my mobo and cpu? If so I'd need a mobo that works with my current ram, or sufficiently cheap ram to replace it.

If so could anyone make some recommendations, my target would be to stay under $200 or so, going much past that would be stretching things ($300 an absolute ceiling).

My last question is in regards to heat. Currently my PSU is on the bottom of my case, and I'm worried how that will affect my GPU cooling (or t he GPU affecting the PSU cooling). Should I try and wrestle my PSU into the proper slot or find some other solution, or just not worry about it?

Thanks a head of time.

Yea, my system pre-part failure resulted from a similar deal, wanted to upgrade one part, which lead to upgrading everything else at the same time. This time it isn't so much an upgrade as it is getting the thing working again, just that it is so old most things are now an upgrade.

You hit the nail on the head, the 939 slot doesn't have any options upgrade wise meaning I'd have to go mobo/cpu combo at least, possibly ram as well.

That is really what I was afraid of, although dropping the video card from4850 to say a 3850 or 3870 could save $50-$75 which could be invested in slightly less thrifty mobo/cpu/ram combo (Assuming my current ram isn't compatible).

Should add I'm only running XP, not Vista.

If anyone else has other suggestions I'm all ears.

Yeah, get the HD 4850.

Then save your money for a new MB+CPU+RAM and maybe a second HD 4850. For example you can get a K9A2 Platinum/Phenom 9850 quad/4GB DDR2-800 for about $400 now, and they'll probably be cheaper in 6 months.

Just wanted to say thanks real quick to everyone for their input, I think for the moment I'm going with the 4850. From what I recall all the parts I have currently are decent overclocking parts, but I would have to invest in a new non-stock hs/fan for my cpu at least, and I may go that route.

So two additional questions:

MSI as a brand. I'm drawn to the new MSI version of the 4850 and am curious about their track record. I've always bought the made by ATI cards in the past, however that isn't an option this go around it seems. are MSI made cards reliable?

Slot 939 X2 coolers, any recommendations? I haven't even started the research on this yet.

AS5 may be the standard, but Tuniq TX-2 is just as good and it's non-conductive (good if you're messy) and doesn't have a cure time (good if you're impatient).