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Computer freezeups, 15 computers
Hi,
We were unlucky enough to experience this problem on a whole classroom of computers (15).
We have Gigabyte Z77M-D3H motherboards.
GSkill DDR3 1600 RAM.
Microsoft USB keyboard and mouse wired 600.
Windows 7 64bit SP1 Enterprise with all patches
We have done quite a lot of troubleshooting so far and this is what we have found:
1) Down clocking the RAM to 1333Mhz helps * but does not fix * this problem. Other forums are saying to change the BaseClock value to 100.1 (BLCK to 100.1). We have not yet tried this option.
Print Page - GA-Z77-D3H freezes suddenly every day
2) We have tried updating the BIOS from the default F4 to the maximum for this board being F8.
Makes no difference.
3) We don't think the problem is due to bad memory, we have tested our memory with memtest for 8 hours with no errors. However see 1), so perhaps some interaction between motherboard and RAM.
4) We have tried burn in tests, but unfortunately these pass since this is a very short lived problem, the mouse and keyboard 'sticks' for 2-3 seconds only. We are not using the keyboard/mouse during the tests, and the computer is stable.
5) Other threads have mentioned fiddling power states, we haven't tried that because this problem happens while people are currently using the computer, not when it's been idle and waking up etc.
6) We don't think it is heat related since even after hours of stress testing the temperatures are no where near manufacturer extremes.
7) We believe the problem is somehow related to USB. We have tried moving the keyboard and mouse to the USB 3.0 ports and that seems to lessen the problem but not eliminate it. We have also tried plugging in a PS/2 keyboard rather than USB, and the problem has not reappeared on that computer for the last 3 days.
8) We also noticed that the problem would mysteriously come and go, with one student thinking that a applied Windows patch 'fixed' it for him for a while.
9) There is no pattern to the freezing. i.e not related to a certain application running or not. Not related to high CPU/Disk/memory utilization. I did notice similar affects of unresponsive behavior when running CPU at 100% with 'high priority' tasks, but that happens anyway on stable computers. Anyway this may indicate when the mouse/kb freezes, the CPU is briefly busy with some USB driver or something.
10) Sometimes when plugging in a USB flash drive the whole computer freezes (e.g no keyboard lights work) and he display changes to a rapidly cycling sequence. Only reset fixes. This has only happened on 2 of the 15 computers however. I think that this thread describes the problem well. Just static discharge I think.
CM HAF-922 Front Panel + Static Discharge Problems. - Power-Supplies-PC-Cases-Case-Mods - CPU-Components.
Any solutions welcome.