Radeon x800gt upgrade help

Correct! It does have a 350W supply and a PCI-Ex16 slot.
The HD4670 is what I`d suggest, it`s much more powerful than your current card
and does n`t need an extra power connector so it`s simple to install.

That type, yes.
Are the connectors what you need? And will the fan fit in your case, it looks quite high and my conflict with other slots?

I`m just being cautious. After all, I do n`t know what is in your case and recommending a card that might conflict with installed hardware or not connect with your monitors would be a little improper of me.

No, I appreciate it. It's the standard 8400 case, it's fairly sizeable - cnet has the width @7.1" with potential spill over from the fan - but I think the biggest I saw was like 6.5" or something. I'm being cautious too, as I am able to do my own comp work, but don't pretend to know anything of the connections and space until I've worked on it. And I've yet to replace a vid card on my own, so here we are. =)

No, it won't. Dell PSU's are generally of outstanding quality. Also, the "requirements" for powering video cards are inflated quite a bit to take into account the low quality PSU's that exist. Consult this chart for actual power draw ratings of modern video cards. You'll find the 4670 somewhere in the 40-50W range, I think.

GDDR4 typically draws ever so slightly more power than GDDR3, which is bad in systems where power is questionable to begin with, but it will (should maybe?) also have slightly increased memory bandwidth, which is a plus.

Seeing as Apollo seems to be the only company consistently throwing GDDR4 (Sapphire now has GDDR4 on 1 version of the 4670, specifically) into ATI cards, and I have no experience with Apollo whatsoever, I can't offer anything in terms of how well it actually works. Their just don't seem to be any benchmarks of the GDDR4 models for comparison's sake at all.

To put purchase worries at ease, if you happen to be shopping and comparing the 4670 models on Newegg, the GDDR4 ones all have standard or 30-day return policies, which means you could return it for refund or exchange if you don't like it's performance.

Also, how about supplying us a full list of all installed components, including the PSU's total wattage and 12V amp ratings? There are tools to find out just how much power you actually need to run the system, like this one.

Incorrect, Dekasav. It draws slightly more power than the X800GT. Look at the chart I linked. See the X800GT at 40W with the HD4670 at 47W? Just a little more power hungry... Not much at all.

Boonality, I have the CM RC-690 case and I absolutely love it.
Also, his X800 is PCI-E.

Now unless focus is really looking for even more graphics power, say for example to play Stalker, FarCry2, GTA IV, or Crysis with all kinds of eye-candy and max or near-max settings, I think he'd be just fine with a 4670. Though, it might be interesting to wait and see just where the release versions of the upcoming HD4750/4770 card(s) stand in comparison. The beta card sure looked great. I'm hopeful the golden version is even better, as I'm considering replacing my 8800GT with a pair in Crossfire.