I've been running an ATI 6970 happily for a while now. I recently was given a GTX580sc as payment for a freelance job. So I of course plugged it in. After some setup I had everything running well. My system is of the home built HTPC variety. My PC connects to my receiver and that goes out to my TV and speakers. All a single digital connection via HDMI. Using the nvidia audio setup I set sound to 5.1. Did the test and heard sound come from each speaker. This was from within nvidia's own CP. Sidebar... My motherboard supports Dolby Digital Live. This is a MUST for HTPC users who want a single cable digital solution for their multi-channel audio needs. Video games output multi-channel PCM and this is something that gets passed out any digital output in 2-channel stereo otherwise. Now to continue... With my ATI card the HD Audio Sound Manager on my motherboard saw the ATI HDMI Audio device and let me control it. i.e. set it to Dolby Digital Live. Thus giving me awesome 5.1 for all my games over HDMI. To my horror I see no Nvidia HDMI output device here! In fact it seems the sound I am hearing must be coming solely from the GTX580s onboard sound. It somehow is not integrating itself in to my systems onboard sound. Thus when I play games I am getting only 2-channel stereo! According to sound manager I have no HDMI connection. :bang: Any ideas or is this the way it is? I might be able to run optical digital audio out from my computer to my receiver and get DDL that way. That's quite a run of cable though. Far from ideal and I might be selling a GTX580sc soon. :\ UPDATE It might just be my $300 Yamaha receiver is saving my butt here. Seems it can see all 5.1 channels of a multi-channel PCM signal! So my games are 5.1. Hell my games are outputting much higher audio quality now because of this. (no more DDL compression) It use to be that receivers would only see 2-channels of MPCM due to bandwidth. I guess this is no longer the case? The death of Dolby Digital Live?