Sound works great in my quad-core Win 7 system until I bring it back from sleep mode at least I think thats whats happening. Installed new drivers a week ago and ever since have had trouble ever since. Have uninstalled the drivers and let start up take care of it. And it does work until I return to the computer later when I then need to restart to get sound back. Once I left Pandora play for hours, and the monitor screen slept. But once I turned it off and unit was in sleep everything came back with a mouse movement except the sound, which needs a reboot to functiion. Device System shows under speakers..Realtec HD Audio and a Realtec Digital Output with Realtec HD Audio under that. Have no separate sound card but using the MSI motherboard sound.