This is an interesting little problem. On one of my computers, it normally supports 9 monitors. 6 monitors on 3 PCIeX16 dual VGA/DVI cards. And the 3 extra monitors by some SIIG USB-to-VGA Pro adapters. A strange thing happened yesterday. Everything was working okay - all 9 monitors were okay... until... Rebooted the box. After reboot, 2 of the monitors no longer get displays. But the symptoms seemed strange. Let's say: Monitor 1, 2, 3, 4, 5, 6 are hooked up directly to the PCIeX16 cards, and monitor 7, 8, 9 are hooked up via USB-to-VGA adapters. When I unplugged all 3 USB-to-VGA adapters, monitor 1 through 6 all worked fine. As soon as I plugged in even one of the 3 extra monitors via USB, monitor 1 and 2 no longer got display. So I could have monitors 3, 4, 5, 6, and 7, 8, 9 (all 7 monitors total). 1 and 2 just wouldn't come on in conjunction with any of 7, 8 or 9. When I unplugged the USB-to-VGA adapters and un-installed the DisplayLink app (driver), monitor 1 and 2 worked fine again and I have a total of 6 monitors all through the PCIeX16 cards. During boot up, BIOS does complain that "CPU overheat, press F1 to continue". But the computer still runs okay, it seems. It seems as if the CPU overheating is affecting the onboard USB interface, and some of the cards on the PCIeX16 bus? Is it possible? I will get a heavy duty CPU heat sink to deal with the CPU overheat error. I hope it will resolve my USB display issue too. If anybody has seen similar strange problem, I appreciate some suggestions. Thank you!
Probably an IRQ conflict between the 1-2 video card and the SIIG card. The BIOS probably recognizes the SIIG card before any of the video cards. Check your startup messages when the system boots. The simple solution might be to reorder the video cards by switching slots. Also, some boards have 2 PCIe slots close together that "share" resources/IRQs. Usually the ones closest to the CPU. Might want to check your board's manual. If the above doesn't work, can you make do with 8 monitors and replace the SIIG with another video card? Regarding the CPU overheating, what happens if you just take the side panels off? If you don't want to keep the panels off, another idea is to install bigger fans to generate more airflow at lower RPMs. It'll be quieter that way. And if you have 2 fans in the same path (like the front and back panels), make sure the air flow travels in 1 direction. Such as having the front fan pulling in cooler air, while the back fan sucks the hot air out.
Thanks for the quick reply, blah12345678. >> Probably an IRQ conflict between the 1-2 video card and the SIIG card. << I have this set up for over 2 years. Not a problem until yesterday. Again, all 9 monitors were working just fine until I rebooted. So something triggered it. The only symptom I had was the "CPU overheating" error. And indeed yesterday was a very hot day and my home office is not A/C too well. >> If the above doesn't work, can you make do with 8 monitors and replace the SIIG with another video card? << Unfortunately no. When I picked the mother board, I only found one that had 3 x PCIeX16 slots. I thought I could drive the additional monitors with the USB-to-VGA adapters. And I can. They worked for 2 years without problem until now. >> Regarding the CPU overheating, what happens if you just take the side panels off? << Maybe I will try your suggestion. >> And if you have 2 fans in the same path (like the front and back panels), make sure the air flow travels in 1 direction. << Yeah. I have been very careful when I first built the box.
Was the reboot after installing software (or a windows update) ? If so, I would roll-back to the prior config.
No. Not that anything I am aware of. Unless I contracted a virus and I didn't notice. I purposely have disabled Windows auto update. I normally don't reboot the box and I run it as long as I can. It is one of my workhorse computers for TradeStation. I checked the Task Manager before I rebooted. 31 days up day. The only reason I rebooted - I noticed that when trying to play a Netflix Instant movie, the screen got chopped up. You know when you call Netflix customer support... the first they ask you is to reboot to see if the problem goes away.
Re: CPU overheating. I've seen instances of the thermal paste between the cpu and the cpu cooler break down over time, you might check that. Decent motherboards will display temp. If yours doesn't use speedfan or similar to monitor.
Thoroughly blow the dust out of your machine (while powered off and unplugged) with some air-in-a-can or compressed air and/or make sure your CPU cooling fan and other case fans are working properly.
Better take the machine outside first.... May want to take out the cards first. Also, concentrate on the fan covers and the cpu heatsink if you have one. Here's an interesting motherboard with 5 PCIe x16 slots: http://www.newegg.com/Product/Product.aspx?Item=N82E16813188130&IsVirtualParent=1
+1. i do this at a minimum every year but prob on average every 6 months. and yes i do it outside b/c the dust you get rid of w/ the compressed air will go somewhere - better outside then in your house.
I'd do a Go Back on the System Restore and see what happens. Sure sounds like registry/ software/ OS related. This flickering event which caused you to reboot, has it happened before?