Hi all, let me introduce my HTPC project. I upgraded to a Pentium 4 Gallatin, and now I can browse web pages. Next step is to watch 1080p youtube without stutter. Now, correct me if I'm wrong, youtube runs in H.264 and Nvidia's Purevideo GPUs can offload that from the cpu and decode it (I could also use AMD gpus but I haven't done much research on their decoding properties). Along with being able to decode videos, I need a PCI interface (unless I want to heat gun an AGP slot onto the motherboard), and a HDMI port for future Surround Sound enhancements. I am on the fence about buying a PSU because I can disconnect my CD and DVD drive to lower power consumption but can't change my 250w PSUs +12v 16 amp rating. I'm not interested in spending more than I have to because I won't be doing anything except watching movies on this computer.
All I've got so far is the Zotac Geforce 610. I was looking at Geforce 8400GS cards, but they don't have HDMI.
I use a GeForce 210 Silent (about $30-$40) on my HTPC. Works great. I have a 3 tuner digital cable card tuner, DVD, BluRay, watch streaming services as well as cable. The only issue with the card - the 29/59 issue (http://experts.windows.com/w/experts_wiki/71.aspx). When watching cable HD channels (select stations), connected to my 60" plasma (1080p), I have the issue.
I moved the HTPC to the bedroom (32" HDTV - only 720p), and it works great - no issue with the 29/59. The issue was not prevalent watching DVD's, BluRays or non-HD channels on Time Warner Cable.
I put an XBox on the plasma - works great - no issues. I can play everything streaming from my HTPC to my XBox.
I have found that using an XBox for a Windows Media Center Extender works great - better than actually running Windows Media Center on the PC (go figure). The video on the XBox is better, and no 29/59 problems.
I am going to convert my HTPC to be just a server, and use the XBox's connected to the TV.
You can get a Radeon HD 5450 for about $30 nowadays too and it will handle HD video no problem, even with Pentium 4. I've upgraded a handful of client's pc's using them when they were on super tight budgets and were experiencing similar problems (choppy video online, etc). It will also depend, however, on what the HD content is encoded at. You'll have no problems playing something encoded at, say 6Mbps, but watching something encoded at 40Mbps wouldn't turn out very well. The Sapphire Radeon HD5450 has VGA, DVI, and HDMI outputs as well, so you'd be covered there as well. However, if it's specifically Nvidia products you're interested in, here's what I'm using in our HTPC right now: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
It's a Geforce GT520 1GB 64bit DDR3, and also has VGA, DVI, and HDMI output. It handles all the HD we can throw at it (youtube, netflix, XBMC) and even plays older games like SIMS 3, GTA San Andreas, etc very well, even on higher settings and at 1920x1080 resolution.
While I would love to find a PCI version of a card for $30, those prices are consistent with PCI-Express cards. Regardless, I am open to AMD cards, with the only requirement that they take some of the work from the cpu when watching video. If this happens, to an extent, with the Radeon HD 5450, then I'm all for it. I'll just have to find one for less than $35. Netflix works fine for me but I can barely run 720p youtube (@ 80% cpu), much less 1080p. So the gpu would have to be pretty good at post processing.