Solved RAM voltage / motherboard compatibility issue

May 24, 2011 at 13:11:19
Specs: Windows 7, Intel core 2 quad, 2.33GHz / 4GB DDR2 corsair

I bought all the parts and put together a PC recently: here are the specs:

Intel Core 2 Quad Q8200 LGA775 'Yorkfield' 2.33GHz 4MB-cache (1333FSB) Processor
Sapphire ATI Radeon HD 4850 512MB GDDR3 TV-Out/Dual DVI/HDMI (PCI-Express)
Corsair XMS2 4GB (2x2GB) DDR2 PC2-8500C5 TwinX Dual Channel (TWIN2X4096-8500C5C)
Gigabyte GA-EP31-DS3L Intel P31 (Socket 775) PCI-Express DDR2 Motherboard
Seagate Barracuda 7200.12 500GB SATA-II 16MB Cache - OEM (ST3500418AS)
Sony Optiarc AD-5240S 24x DVD±RW SATA Dual Layer ReWriter (Black) - OEM
Coolermaster 460W eXtreme Power Plus PSU - 20+4pin 4+4 ATX12v 4x SATA 6pin PCI-E

I'm trying to run it in Windows 7 ultimate-64 bit. Unfortunately it was unstable.

Started off with boot issues as voltage to RAM was too low-so set RAM voltage to auto on BIOS. This ran fine for usual operation until about 2 hours where comp would crash, also high demand task would cause crash. Three times one stick of RAM was damage by crash and subsequently replaced under warranty- with the issue looking like OEM problem! Not likely.

Got fed up with crashes and instability so tried installing 32-bit windows 7. Still unstable but less so. Finally tried dropping the voltage to the RAM back down on BIOS(to 1.1V). The computer will now not output video on start up-no access to BIOS!!!

Upon powering up the mb lights-up (one 'on' red LED and 4 red, yellow, green green LEDs by the RAM) and the graphics card has power.

How do I get my PC back, how do I get stability and is the answer get a better motherboard and set the voltage to 1.8 and not put it on auto voltage!?!

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May 24, 2011 at 15:22:59
✔ Best Answer
First thing I see is that your PSU is too small. That PSU has 2 +12V rails @18A each. Your HD 4850 draws almost 11A at idle and almost 21A at full power. One of your 12V rails is feeding the Graphics, which can't put out enough wen you are taxing the card. The other rail has to feed the CPU, drives, RAM, motherboard, fans, etc. CPU draws over 5A.

Get another PSU. You should use a single rail unit with at least 40A on the 12V rail.

What is the required voltage of the RAM you have? What is the exact part number? If the RAM is supposed to run at 1.8V and you are having problems then there may be something wrong with your RAM, Motherboard or PSU.

Try running memtest86 from a boot disk. Get it from the link below. No errors are acceptable.

See the links below.
Divide the wattage by 12 to get the Amps on the 12V rail which is where the card draws from.

Note: You get what you pay for. Look at the warranty periods. 2 to 5 years.

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May 24, 2011 at 15:41:10
Auto voltage is all I have ever used - never a problem. Under voltage is just as bad (or worse) as over voltage on electronics. The version of Windows should not matter, unless the source is questionable. Genuine works best!
Check the chart for the diagnostic LED's in the owners manual. Reset the CMOS to factory. Re-seat the CPU and RAM (be sure all power source are removed).

Get it running 'solid stock' before you try tweaking the system.

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May 24, 2011 at 16:44:18
"Auto voltage is all I have ever used"

I rarely use Auto. There's no guarantee the BIOS will detect the voltages (or any other setting) properly when "auto" is selected. Check the RAM manufacturer's specs & manually configure the RAM settings accordingly. If it states 1.85v, 1.9v, 2.0v, etc, that's what you should be using. Same goes for the RAM timings. And since you have a 1333MHz FSB CPU, you should be running the RAM at 667MHz, not 1066MHz.

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Related Solutions

May 25, 2011 at 10:50:37

Thank you all for your comments, all helpful. I will start by buying a new power supply, will check the RAM specified voltages and check the mb manual.

However, the problem still remains that I can't get to a BIOS screen to change anything-how do I deal with this? Do I- remove all power sources from mb, i.e. cable and battery (will this clear the BIOS back to default or just screw up the mb? Do I have to buy a new mb; or is there another option?

Again, thank you guys

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May 25, 2011 at 11:20:41
Are you using a USB or wireless keyboard? If so, switch to a PS/2 keyboard and start tapping the del key as soon as you start the computer. That should take you to the BIOS screens.

In order to use the USB keyboard in the future you can enable the selection for legacy USB support.

Download HWmonitor to see the temperatures and voltages while under power. This may show why you are dropping out from time to time. I think you are stressing the PSU. Get HWmonitor from the link below.

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May 25, 2011 at 11:23:57
I've got a USB but I'm using the USB->PS/2 converter, and I've tried furiously tapping the del key! bad times

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May 25, 2011 at 11:27:06
The USB/PS/2 adapters only work if the keyboard is designed to use them. Obviously yours isn't. Borrow one if necessary.

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