I have ample power supply, so that's not a factor. I'm running still WinXP have a 1920x1080 23" monitor. What I want to figure out is this:
Will either of these two card be bottlenecked by the components I listed above? This is my older AGP system I still use on the side for when friends come over and we're playing together and also acts as my HTPC on my 40" Samsung LCD. Right now it has the EVGA 7800GS AGP http://www.newegg.com/product/product.aspx?item=N82E168... in there and run fine but I'd like a little better.
Well, with a dual-core CPU, if there is a bottleneck, it ought to be minimal. Mostly it's the old single-core P4s (and their AMD equivalents) that you'd worry about that with. The RAM and motherboard should not have any negative effects either.
So I'd say the 3850 is going to be fine as long as you have the right power connectors -- the one you linked to takes an 8-pin plug, so double-check you have one of those or at least a 6+2.
Depending on what you're after on the HTPC front, though, you may want to opt for a 4670 instead, because you can get an HDMI output.
^ the 3850s and 3650s also output over HDMI, if they have the included adapter
Hah, a crazy little VIA board. Anyway, I say go with the Radeon 3850. It is way faster than the 3650. Depending on the game, a Radeon 4670 may edge it out though. Anyway, your CPU should not be a bottleneck for a single Radeon 3850 and is a good match. Get the 3850 and be happy.