I have not been impressed at all with nvidia tv out. I have only used it up to GF3 though. I picked up an ~ $40US ATI radeon 7000 oem with tv out and it works perfectly. If you really need both video in and video out then I can't really speak from experience. Maybe a PCI tv tuner card + the radeon 7000 would get you where you want to go? Otherwise there are relatively low end all in wonders (7500 I think) that aren't too expensive.
My advice would be to just set up a separate box for HTPC duties. This way you can keep your beefy system for gaming and upgrade the video in it as needed without having to buy an all in wonder type card every time.
|