BleepingComputer.com: Strange memtest failure after leaving PC off

I've been working on this for a month and I still have no idea what the heck is wrong with my newest build.

First some some background. I built two computers, both using the Gigabyte ga-ma770t-ud3p, AMD phenom 550, and a 4850 (but of different brands). Build 1 is OK. No problems. Build 2, however had a strange problem - if left off for more than a few hours, it'd completely fail in memtest, creating thousands of errors all with a bit error of 00800000. However, if build 2 is power cycled, all is well again, until it's left off for a few hours.

So of course I think something is defective. I start switching parts, one at a time, and replacing the last switched part back and running memtest on both build 1 and build 2 to cross check.

But despite switching EVERY component, and doing EVERY thing I can think of, build I STILL have the same error.

Things I tried:

• Swapping CPU's
  
• Replacing the motherboard (originally build 2 had Rev 1.0, but now after RMA it has Rev 1.1. Exact same errors)
  
• Swapping RAM
  
• Swapping GPU's
  
• Swapping PSU's
  
• Swapping CD drives
  
• Swapping BIOs settings
  
• Resetting the BIOs

I'm out of ideas, the only part I haven't tested is the case, and that can't be part of the problem.

Just Have the MOBO replaced on your warranty, i cant see anything else you can do, have you checked clock speed? Are you attatching HD's that's the only thing you havn't mentioned

This post has been edited by longtooth: 10 January 2010 - 01:36 PM

longtooth, on Jan 10 2010, 01:33 PM, said:

I ran the tests with no HD's attached. I replaced the motherboard but still, the exact same error. The new one even has a new firmware and is a new revision.

Alright guys here's what happened. Turns out it never occurred to me that one of the RAM modules that I tested to be working could be at fault. I tested all the modules several times, but I never tried switching a "good" module (it passed all tests otherwise) into the working build and powercycling it. Man, I order 4 sticks from G.skill and 3 of them are defective...

that happens sometimes. Ive never used g-skill but i have friends who have and never had a problem with it, but defective parts always happen. Funny story is that I built a system using Patriot ddr3 2000 mhz. well, the motherboard didnt support 2000 mhz but the memory automatically downgraded to 1600 mhz np. that wasnt the problem anyway, it kept BSODing on me. I couldnt figured out why so I ran memtest and got 4 errors, so I dropped the ram down to 1000 mhz, and ran memtest-passed with flying colors. So i did some research, come to find out the memory needed to run at 1.65v and the motherboard defaulted to 1.5v. so, low and behold I upped the voltage, problem solved. Stuff happens. anyway, hope your replacement memory works. :D