Question memtest86 errors, only above 4GB

Feb 26, 2022
10
0
10
0
I'm trying to revive an old PC where I started to see Windows bluescreen errors a few months ago. I don't remember the exact errors on the blue screen, but they led me believe there were memory errors.
Running memtest86 confirmed my suspicion, one of the system's 2GB module did not work, so I bought 2x4GB Kingston KVR16N11/4 as replacement, but I'm still getting errors now.
I sent the 4 GB modules back thinking they were broken, but after testing the modules in the shop they did not find any memtest86 issues.
So I started to run my own tests to figure out what is going on.

My current configuration running memtest86:
  • MSI 760GM-E51 motherboard (4 memory slots, max 16 GB)
  • AMD Phenom II X4 955 CPU
  • ASUS BRAVO 220 SILENT graphics card
  • Seasonic S12II-330 PSU
I also tried testing with different components, just to eliminate a possible PSU/CPU/VGA or motherboard error:
  • Gigabyte GA-M68MT-D3P motherboard (2 memory slots, max 8 GB)
  • AMD Athlon II X2 245 CPU
  • PNY GeForce 9600 GT XLR OC graphics card
  • Corsair CMPSU-520HXEU PSU
I tried replacing CPU, VGA, PSU individually and at the end I completely switched to the other motherboard, but the memtest86 error kept on occurring every time I inserted more than 4 GB ram into any of the motherboards.
To narrow down the problem I took the "current config" above, and started to test different memory configurations of the following memory sticks:
  • 2x1 GB Kingston DDR3-1333 KHX1333C7D3K2/2G RAM
  • 2x1 GB Kingston DDR3-1333 KHX1333C7D3K2/2GX RAM
  • 1x2 GB Kingmax DDR3-1333 FLFE85F-C8KM9 RAM
  • 2x4 GB Kingston DDR3-1600 KVR16N11/4 RAM (non-kit)
The result of the tests, what works OK:
  • All sticks work fine when inserted alone (all of the modules were tested at their rated speeds, so DDR3-1600 @ 1600, and DDR3-1333 @ 1333, however I noticed the 1 GB modules run at 1280 Mhz by default, at least according to memtest86)
  • All 4 memory slots work fine on the motherboard (I run at least 1 single-stick test for each of the 4 slots)
  • Multiple memory modules work fine together, including weird setups like 1+2+1 GB
  • Dual channel configuration also works fine, so a 1+1+1+1 GB setup works fine (although I'm not sure memtest86 was actually running in dual-channel mode, but at least this is a dual-channel setup)
What DOES NOT work OK is going beyond 4 GB in any configuration. I get thousands of memtest86 errors in Test #2.
  • 1+1+1+2 GB (@1333Mhz) - does not work, errors start at 100% in Test #2
  • 4+1 GB (@1333 Mhz) - does not work, errors start at 100% in Test #2
  • 4+2 GB (@1333 Mhz) - does not work, errors start at 89% in Test #2
  • 4+4 GB (@1600 Mhz) - does not work, errors start at 69% in Test #2
  • 4+4+1+1 (@1333 Mhz) - does not work, errors start at 56% in Test #2
What is even weirder that I can reproduce the same problem using the Gigabyte motherboard and the X2 245 CPU - so if it is a motherboard, BIOS, or motherboard setting related issue, then strangely the completely different second motherboard has exactly the same problems.
  • 4+1 GB (@1333 Mhz) - does not work, errors start at 100% in Test #2
  • 4+4 GB (tested both @1333 Mhz and @1066 Mhz) - does not work, errors start at 68% in Test #2
Please note that the only difference between the failing and successful test runs is the amount of memory: <=4GB - success, >4GB - failure.
So there is either no support on this platform for 4+ GB :p , or somehow I managed to disable or broke it.
Can someone give a hand? :) Thanks!
 
Last edited:
Feb 26, 2022
10
0
10
0
when running above 4GB, ram should default to 1333MHz
you probably will need to overclock northbridge frequency to have stable 8GB ram at 1600MHz
I experience the exact issue over 4GB regardless of the frequency. I have failing test runs above 4GB @1333Mhz as well as @1600Mhz. (I just updated the original post with this information.) When there are 1333Mhz modules in the mix, I run the test @1333Mhz. So this is not an overclocking scenario.
 
Last edited:
Feb 26, 2022
10
0
10
0
ram is mapped by CPU memory controller, if its memory matrix issue, then either you have to manualy setup ram timings or replace CPU
I tried the tests with two CPUs, an Athlon II X2 245 and a Phenom II X4 955, with exactly the same results in both cases. Could the problem still be CPU related?
 
Feb 26, 2022
10
0
10
0
do you have 64 bit memtest? as 32bit would be limited to 4GB
I'm using v5.01 from the Ubuntu install media. It supposed to support up to 2TB RAM ("Added support for up to 2 TB of RAM on X64 CPUs").
When memtest86 starts, it displays "X64 mode" on screen - hope this means that it is running in 64 bit mode.
 
Feb 26, 2022
10
0
10
0
it should, but just in case something wrong with that memtest, can you try this one?
5.x is few years old, latest is 9.x
I tried "HCI Design's MemTest" under Windows 10 and was able to run a successful memory test covering 6GB of the installed 8GB (in total 90% of the memory was used and I saw no errors anywhere). This suggestst that indeed I have a memtest86 issue somewhere.
Will try a never version of memtest86 as soon as I can make a version that boots on a non-UEFI system...
 
Feb 26, 2022
10
0
10
0
I don't know how to make UEFI memtest86 work on my old system, but since I'm not getting memory errors with other memory test tools, I'm giving up on memtest86 for now. Thanks for all of your help.
 
Feb 26, 2022
10
0
10
0
maybe post some minidumps if you have bsod, could be some rogue driver
After replacing the failing memory module to 2x4GB Kingston KVR16N11/4, there were no more issues in Windows, I only got errors in memtest86 (for the 4+ GB part). So as far as I can tell, it is more likely a user error on my end (I'm using memtest86 in the wrong way or I'm using a wrong version) than an actual memory issue.
 
Feb 26, 2022
10
0
10
0
I don't know how to make UEFI memtest86 work on my old system, but since I'm not getting memory errors with other memory test tools, I'm giving up on memtest86 for now. Thanks for all of your help.
I just completed a test run with Windows memory diagnostic tool, and there were no memory errors. It is a confirmation that I'm screwing up something with memtest86, but since my old system does not support UEFI, I won't be able to run a test with the latest version of memtest86. Right?
 

ASK THE COMMUNITY