System insomnia! Wakes up after 50 seconds after going to sleep

Question

My desktop won't stay asleep. It consistenly wakes back up after approximately 50 seconds.

This happens regardless of whether I manually select Sleep from the start menu, or if it goes to sleep on its own.

System Specs:

• Windows 7 64-bit Service Pack 1 (problem also existed prior to service pack)
• ASUS M3N78-VM motherboard.
• AMD Phenom II X6 1055T Processor 2.80GHz
• 8 GB Ram
• Samsung SSD 830 Series 64GB SSD drive (boot drive)
• 2 SATA HDDs mirrored with onboard NVIDIA RAID AMD Radeon
• HD 6950 Video Card (problem existed before this was added)

All devices in Device Manager appear to have the correct device drivers. No yellow exclamations.

Things I've tried:

• BIOS set to S3 Only (previously set to auto)
• All "Power On By" options in the BIOS set to Disabled
• Unplugged all USB devices (including KB/Mouse), Network Cable, and Monitor Cable
• Unchecked "Allow this device to wake the computer" on Network Interface
• Disabled the "USB selective suspend setting" in advanced power options.
• powercfg -devicedisablewake for all devices that show up in the "wake_armed" list

powercfg -lastwake reports:

Wake History Count - 1
Wake History [0]
Wake Source Count - 0

I have several events in the system event log that look like this:

The system has resumed from sleep.

Sleep Time: ‎2012‎-‎01‎-‎21T15:18:12.274800000Z
Wake Time: ‎2012‎-‎01‎-‎21T15:19:23.638800000Z

Wake Source: Unknown

If anyone has troubleshooting suggestions for this, I would greatly appreciate them as I'd like to solve this problem so my computer can get a good night's rest!

Answer 1

Did you check for waketimers? In your advanced power options, try disabling the wake timers (under "sleep"). If that fixes the problem, check under powercfg -waketimers, that should give you an idea of what is waking it.

Answer 2

powercfg includes a nice switch which can output a detailed report of possible items which are using more power than needed in your system (especially good for notebooks) or which are preventing a system from being as energy efficient as possible.

powercfg -energy

Run that command from an elevated cmd prompt and then launch the created HTML report (auto saved in the current path powercfg is run from) to see possible issues that need to be addressed.

Guided Help: Get a detailed Power Efficiency Diagnostics Report for your computer in Windows 7

Answer 3

I have found that "most" of the time it is an "external event." You mentioned unplugging all USB devices and that is often the problem as well as the possibility of other ports including the LAN. Could it be the power supply or a UPS?