PC unstable at stock: Problem with CPU, RAM or Mobo? - Hardware & Software

Just over a year ago I build a gaming PC with the following specification: - Intel Core i5 750 - 2x2GB DDR3 1333MHz Crucial Ballistix - ASUS P7H57D-V EVO Motherboard - ATI 5770 1GB - Samsung 1TB - OCZ ModXStream Pro 600w - Windows 7 Pro - Ubuntu Linux Now, the problem is that sometimes when I do stuff semi-intensive (e.g. Playing a game) the system sometimes crashes (In both Windows and Linux). Doing tests, I got these results: - IntelBurnTest: Unstable CPU - Prime95: Rounding Error - Memtest86+: Memory Errors (Not often and do not repeat on each test) - Intel Processor Diagnostic Tool: No Problems Now, doing the same tests with only one stick of RAM in, I get no errors. Nothing is overclocked and are set at stock speeds. RAM latency and voltage set manually according to what's printed on each module, as the Mobo auto was getting the info wrong (9 instead of 7 latency, and 1.2V instead of 1.65V). I have contacted Intel before, they say they will only accept an RMA if the processor fails the Intel Diagnostic test. Any ideas what's at fault here?

Your RAM is the fault if it's stable with 1 stick which seems to be the working one. As if your RAM was working correctly it wouldn't give out any errors.

[QUOTE=TheTiger;30888275]Your RAM is the fault if it's stable with 1 stick which seems to be the working one. As if your RAM was working correctly it wouldn't give out any errors.[/QUOTE] It's stable when I test each stick individually, it errors when both are used.

[QUOTE=1solidsnake2;30889586]It's stable when I test each stick individually, it errors when both are used.[/QUOTE] That's weird then. I guess it's something to do with the motherboard or CPU then but it's hard to test without other motherboard if you don't have expensive software like Eurosoft PC-Check.

Get Memtest86+: [url]www.memtest.org[/url] And make a bootable floppy/CD/USB key and run memtest for probably 6 hours at minimum, unless it finds problems right off the bat, and you know you have bad memory. I would test each stick individually, unless you know how the memory is mapped on the motherboard and can tell which stick it is.

[QUOTE=bohb;30890381]Get Memtest86+: [url]www.memtest.org[/url] And make a bootable floppy/CD/USB key and run memtest for probably 6 hours at minimum, unless it finds problems right off the bat, and you know you have bad memory. I would test each stick individually, unless you know how the memory is mapped on the motherboard and can tell which stick it is.[/QUOTE] Already have: [QUOTE=1solidsnake2;30882290]Doing tests, I got these results: - IntelBurnTest: Unstable CPU - Prime95: Rounding Error - [b]Memtest86+: Memory Errors (Not often and do not repeat on each test)[/b] - Intel Processor Diagnostic Tool: No Problems[/QUOTE] Only got memory errors when both sticks were in. I will try again however, testing each stick individually and both sticks, probably one test per day for the duration of the day.

I've tested each stick of RAM individually and together with MemTest86+ overnight (each test on each night) and there was no errors. I then start stress testing the CPU with IntelBurnTest, I left it running, when I came back later I got greeted with this: [IMG]http://i.imgur.com/Mh2tP.jpg[/IMG]

[QUOTE=1solidsnake2;31098210]I've tested each stick of RAM individually and together with MemTest86+ overnight (each test on each night) and there was no errors. I then start stress testing the CPU with IntelBurnTest, I left it running, when I came back later I got greeted with this: [IMG]http://i.imgur.com/Mh2tP.jpg[/IMG][/QUOTE] You either have defective RAM, or you aren't running the RAM at the rated voltage. Undervolted memory can cause #2 and #3, but so can defective RAM. I've seen 3 types of general RAM failures: 1) Outright bad memory (spews out errors when memtest is run at predictable regions in memory.) 2) Memory that will work fine, or mostly fine until you put a load on the sticks and they eventually fail. 3) Memory that fails when put in dual channel mode (I really have no idea why this happens.) If you're sure you're running the memory at its specified voltage, then you should probably RMA all of your RAM and not just one or the other stick.

[QUOTE=bohb;31109464]You either have defective RAM, or you aren't running the RAM at the rated voltage. Undervolted memory can cause #2 and #3, but so can defective RAM. I've seen 3 types of general RAM failures: 1) Outright bad memory (spews out errors when memtest is run at predictable regions in memory.) 2) Memory that will work fine, or mostly fine until you put a load on the sticks and they eventually fail. 3) Memory that fails when put in dual channel mode (I really have no idea why this happens.) If you're sure you're running the memory at its specified voltage, then you should probably RMA all of your RAM and not just one or the other stick.[/QUOTE] The RAM voltage is manually set to 1.65V as stated on the sticks themselves. But if it was a RAM error, surely MemTest would have picked it up?