Here's an image of what I see when it happens. Apologies for quality, as it's from a camera-phone:
It's very intermittent. Sometimes it occurs a couple times in a day, other times I'll go over week or two without incident, all with no discernible pattern or change is usage behavior.
When the machine locks, it generally starts to stutter badly if it's being used to watch video or play a game. The stutter includes the audio, but once the PC totally locks, the audio cuts out. It's totally unresponsive and requires a hard reset. It's happened when I'm not looking at the screen (idling with screensaver, some hobby cryptocoin mining, etc), so I can't say 100% that there is always a stutter. I've not had this running hot for extended periods of time doing cryptocoin mining. At most, it runs a miner overnight or for a few hours when nobody is using it (this machine is the living room HTPC for a family of 4).
Nothing appears in the Event Viewer other than the typical error messages stating that the previous shutdown was unexpected. Never any smoking gun prior to the lock.
Machine details:
RAM has been through Memtest86 and passed.
I've used Furmark to do a burn in on the gpu and I've not seen it crest over 60C. Last time I did it (today, 2/8/2014) I never saw a temp above 57C. (I've also never seen a temperature above 52C while running a cryptominer, generally in the 40s.).
CPU never seems to run too warm. I keep a widget on my desktop with the core temps for both cores, and they spend most of their time sub-40C. I've yet to torture them with Prime95, but I've not seen any reason to think it's CPU related yet.
I've turned on Windows Driver Verifier and gave it some light and heavy loads (streaming Hulu, turning on a crypto miner, Furmark while driver verifier was enabled, etc) and nothing triggered a BSOD. When I did get one of the freezes, there was no BSOD or minidump to analyze.
This issue has persisted through a PSU replacement, so it's highly unlikely that power is the culprit.
I've run a HDD tester from Seagate on my "media" HDD and found no problems.
I've run an SSD benchmarker (Crystal Disk Mark) and nothing failed and the numbers seemed reasonable.
All of the important and most of the optional Windows Updates are installed.
I'm having trouble figuring out the source, especially since I can't reliably stimulate the system to reproduce the issue. Any ideas?
It's very intermittent. Sometimes it occurs a couple times in a day, other times I'll go over week or two without incident, all with no discernible pattern or change is usage behavior.
When the machine locks, it generally starts to stutter badly if it's being used to watch video or play a game. The stutter includes the audio, but once the PC totally locks, the audio cuts out. It's totally unresponsive and requires a hard reset. It's happened when I'm not looking at the screen (idling with screensaver, some hobby cryptocoin mining, etc), so I can't say 100% that there is always a stutter. I've not had this running hot for extended periods of time doing cryptocoin mining. At most, it runs a miner overnight or for a few hours when nobody is using it (this machine is the living room HTPC for a family of 4).
Nothing appears in the Event Viewer other than the typical error messages stating that the previous shutdown was unexpected. Never any smoking gun prior to the lock.
Machine details:
OS: Windows 7
CPU: Intel Pentium G645 2.9GHz
Mobo: H77MU3 LGA 1155 mATX
PSU: CX Series CX600M 600 Watt ATX Modular
RAM: Ballistix Sport 4GB DDR3-1600
GPU: SAPPHIRE 100355OCL Radeon HD 7850 2GB 256-bit GDDR5 (OC version)
OS SSD: SSDNow V200 SV200S37A/64G 64GB SATA
Media HDD: Barracuda 2TB 7,200 RPM SATA
some SATA DVD burner
some cheap media card reader
some cheap USB3.0 hub that slots into PCI
using a Samsung HD TV as a monitor, connected via HDMI.
All hardware is factory-default, no overclocking or other mods done.
Catalyst Driver: 13.11
AMD Audio Driver: 7.12.0.7717
RAM has been through Memtest86 and passed.
I've used Furmark to do a burn in on the gpu and I've not seen it crest over 60C. Last time I did it (today, 2/8/2014) I never saw a temp above 57C. (I've also never seen a temperature above 52C while running a cryptominer, generally in the 40s.).
CPU never seems to run too warm. I keep a widget on my desktop with the core temps for both cores, and they spend most of their time sub-40C. I've yet to torture them with Prime95, but I've not seen any reason to think it's CPU related yet.
I've turned on Windows Driver Verifier and gave it some light and heavy loads (streaming Hulu, turning on a crypto miner, Furmark while driver verifier was enabled, etc) and nothing triggered a BSOD. When I did get one of the freezes, there was no BSOD or minidump to analyze.
This issue has persisted through a PSU replacement, so it's highly unlikely that power is the culprit.
I've run a HDD tester from Seagate on my "media" HDD and found no problems.
I've run an SSD benchmarker (Crystal Disk Mark) and nothing failed and the numbers seemed reasonable.
All of the important and most of the optional Windows Updates are installed.
I'm having trouble figuring out the source, especially since I can't reliably stimulate the system to reproduce the issue. Any ideas?