memtest89 shows sometimes errors somtimes not?

[HL1234]

Hello,
I got trouble with some old computer. Fitful I get blue screens. Normally I should get fixed it by myself because I'm experienced in commuter technology. But I get every time an other blue screen message, so I suppose that it could some ma be wrong with my RAM:
Corsair 2 x 2GB DDR2 800 Dual Channel and
Qimonda 2x 1GB DDR2 666.
I have more then one OS installed (different Windows). Both get blues screens. I checked both hard disk with CristalDiskInfo. It says hard disk is "Good" for both.

I test the ram now with memtest89 v.4.3.7. I got some errors in Test 7 + 13 called: "65535+". In between the test I downloaded with my other PC the new version 5.0.1 of memtest86+. I test the RAM of PC 1 with it again, but I get no more errors. I rebooted the PC and test it within Windows 8, with a program called "memtest64". It run's, but then the PC suddenly freeze. I reboot and test it again, but with the old memtest89 version v.4.3.7, what have shown errors before. But after pass 1 there are no more errors shown.

Because all of that, I described, I do not understand why there are some times errors and why now no more again?
I experienced with this PC when it stands long time (days) off and I started it, I got blue screens. After a while when it runs sometimes it runs the whole day without problems - strange?

And second, what is the conclusion of this - is my RAM now defect or not?
What do you think - thank you for help.

[David (PassMark)]

memtest89 shows sometimes errors

I think you mean MemTest86 and not 89.

the new version 5.0.1 of memtest86+

V5.0.1 of MemTest86+ is now old. And it isn't our software in any case.

V7 of MemTest86 (without the plus) is the current release.

Different tools test in different ways. Plus the environment can change from one day to the next.

Anyway, RAM is very likely bad. Just replace it.

[HL1234]

Hello,
thanks for your response. Yes I mean memtest86.
Why do you think the RAM is "very likely" bad?
After the the first test with error memtest86 I didn't find more any errors. But I get further BSOD's. I downloaded the new version V7 of memtest from here but it runs only memtest86 4.3.7 because of my old PC. And also I see *no* errors. I did not understand why it find errors the first time testing?

"the environment can change from one day to the next." I have nothing changed in the computer.

The BSOD comes late in the starting process of the OS.
Virus check didn't found anything, also Malewarebytes.
Hard disk seems to be Ok.
Windows 8 Pro has the latest updates.
Both Windows 8 (x64) and W2k12 (x64) (private use) crashed. WinXP and W2K3 on the other hard disk I have not tested, because the will be replaces and are (x86) Versions and can not allocate the whole 6 GB of RAM. I has been told the board can only address up to 6GB of RAM, so I has not try to use more RAM:
2 CORSAIR "Value Select" 2 x 2 GB form 2012 for Dual-Channel unbuffered
2 Quimonda 2 x 1GB from 2007 for Dual-Channel unbuffered (since equipment acquisition) .
In BIOS I have take the default values for the RAM (no overclocking)

When I can Login in the OS and it runs without BSOD, it runs the whole day. Is there any experience that RAM can work on some days and on other days not? Sounds for me very strange.

[David (PassMark)]

Why do you think the RAM is "very likely" bad?

Because you ran a memory test and the RAM failed the test.

[HL1234]

Sorry, maybe my english not so good.

My question is: After the the first test, memtest86 do not find any errors - what does this mean?

and
what does this mean: "the environment can change from one day to the next."?

Thank you again.

[David (PassMark)]

Fault might be intermittent. Might be temperature related. Might be some particular random data patterns that triggers it. Might be external or internal EMI. Might be cosmic rays.

[HL1234]

I found out know that I had to change the CPU. After that the PC seems to be stable.
Thank you for your help .