Win7 wakes from high def audio bus right after being put to sleep

Hi,

I've had this problem every since I built my new rig - the thing either won't go to sleep, or will wake back up if I put it to sleep manually. It doesn't do it all the time, but it happens enough to be an annoyance.

Here's what powercfg says after it wakes up:

Code:

C:\Users\Charles>powercfg -lastwake
Wake History Count - 1
Wake History [0]
  Wake Source Count - 1
  Wake Source [0]
    Type: Device
    Instance Path: PCI\VEN_1002&DEV_4383&SUBSYS_A1021458&REV_40\3&18d45aa6&0&A2
    Friendly Name:
    Description: High Definition Audio Controller
    Manufacturer: Microsoft

I also ran powercfg -energy, as suggested in an older thread and it spit back:

Code:

System Availability Requests:System Required Request
    The device or driver has made a request to prevent the system from automatically entering sleep.
      Requesting Driver Instance  HDAUDIO\FUNC_01&VEN_10EC&DEV_0889&SUBSYS_1458A102&REV_1000\4&19288c9a&0&0001 
Requesting Driver Device  Realtek High Definition Audio

I've googled around a bit and most things say to modify the "power management" of the high def audio bus, but there is no power management tab for me to configure.

System specs:

Phenom II x4 3.4Ghz,
Gigabyte GA-870A-UD3
8GB DDR3
Win7 Pro x64
Nvidia GXT560 Ti

I'm running updated drivers as well.

Any ideas? I didn't have this problem with my old rig.

Yep, there was no power management tab in device manager for the high def audio bus. I turned off PME event wake in the BIOS, but I don't think that's going to have any effect.

Drivers are the latest version.

It's strange, cuz it usually happens after playing a video game, even if I close it out 30-45 mins prior to putting it to sleep. Once it wakes up and I put it back to sleep, it stays asleep, which makes it all the more puzzling.