Homebuilt system randomly crashing. Possible bad PSU?

[FluffyWaffles]

I have a homebuilt system that has been having issues with crashing and restarting for about a month and a half. The crashes are random with no apparent pattern to the frequency or timing; sometimes they occur 2 minutes after startup, other times after 3hours of usage (varying activities of sometimes web browsing to playing graphic-intensive games).

My system Specs are:
AMD FX 8350
ASUS M5A99FX Pro R2.0
Cooler Master Hyper EVO 212 (with an additional 3-pin fan)
2 ASUS GTX 660 Ti (in 2-way SLI)
Corsair Vengance 8gb DDR3 RAM (CML8GX3M2A1333C9)
ThermalTake Smart 750w PSU
124gb SanDisk SSD
WD 2TB Green HDD
Cooler Master HAF 912 Mid tower
2 200mm case fans
140mm case fan
Windows 8 64bit

I have noticed that when the crash causes a fail to POST (CPU LED also goes red) that just replugging my computer into a different wall makes the computer run perfectly fine again until the next crash, which then goes back to being a gamble of if POST goes through or not.

I think that it is possibly a faulty PSU, but I just want to make sure with someone who knows their stuff before I go off and try to replace it.
This is also my first homebuilt system if that didn't come across in my amateur opinion above. I would like to save where I can since I also do not have a budget for very many replacements.

Any help is appreciated.

 

[Proximon]

The PSU is not the worst they make. A CWT built unit. A small short somewhere could cause similar issues. I doubt you will figure it out without swapping out the PSU. Things you could try first...

Try each stick of RAM individually.
Verify that RAM voltages are what are expected using CPU-Z
Use HWMonitor to check your temps.
Use a multimeter to check the PSU voltages.

If you have another GPU to test that's a good plan as well. GPUs can do odd things occasionally, and because of modern system speeds sometimes an attempted restart does not allow time for GPU memory or system memory to fully clear.

If you really HAVE to unplug the system before it will restart, you are either shorting out somewhere or the PSU thinks you are.

 

[FluffyWaffles]

I haven't yet tried each stick of RAM individually on my system yet, I will try that out once I have the chance.
According to CPU-Z, my RAM voltages are 1.5V (I believe that it is the normal, correct me if I am wrong).
My temps on HWMonitor never go past 50C on my CPU even during a Prime95 test and my GPUs dont hit 80C unless I do a FurMark test for 15+ minutes (plateaus at that point). CPU socket I believe never goes past 61C during Prime95, I will double check later.
Don't have a multimeter, so I cannot check just yet. Where can I get one for cheap?

Just an extra note, nothing on my system is overclocked, everything is on stock settings.

 

[ubercake]

Another thing to consider if this is your first PC build...

Did you mount your motherboard directly to the motherboard tray or did you use the standoffs? If you did use standoffs, did you use extra standoffs by chance?

 

[FluffyWaffles]

Did you mount your motherboard directly to the motherboard tray or did you use the standoffs? If you did use standoffs, did you use extra standoffs by chance?

The motherboard is only on the supplied Standoffs, I did not use any extra outside what was supplied and stated in the motherboards manual.

 

[FluffyWaffles]

Update: I am testing my RAM on my computer with memtest86 and have gotten an error in my second stick. Does this mean I will have to get a replacement set of sticks(it was an error on a single bit)? If so, can I run my system on one stick until I can get a replacement and also any recommendations on replacements?

 

[Proximon]

Well, maybe Corsair would RMA one stick If not, and you don't want to wait, you really can't go wrong with Corsair, G.skill.... really I don't think we have a bad RAM brand these days. Even Patriot and Wintech seem fine. I can't imagine why bad RAM could cause all these symptoms, but if you can run with no crashes on your one stick you have your answer. There is nothing wrong with just using the one stick.

 

[FluffyWaffles]

Going to RMA the sticks together since corsair doesn't allow you to send them only one of two. I'll have to bear without using my computer until they send me back sticks to figure out if that solves my problem. How long does an RMA take to get me back my Ram anyways?

 

[ubercake]

Did you mount your motherboard directly to the motherboard tray or did you use the standoffs? If you did use standoffs, did you use extra standoffs by chance?

The motherboard is only on the supplied Standoffs, I did not use any extra outside what was supplied and stated in the motherboards manual.

Going to RMA the sticks together since corsair doesn't allow you to send them only one of two. I'll have to bear without using my computer until they send me back sticks to figure out if that solves my problem. How long does an RMA take to get me back my Ram anyways?

I had to RMA a set of sticks with them a couple of years ago and it took less than a week. Hopefully, they have the same turnaround for you!

 

[FluffyWaffles]

Update: I have gotten new ram sticks that are all working properly and am still having crashes on stock settings, no overclocking. I am starting to think my motherboard is bad, but is that possible?

 

[Proximon]

I have noticed that when the crash causes a fail to POST (CPU LED also goes red) that just replugging my computer into a different wall makes the computer run perfectly fine again until the next crash, which then goes back to being a gamble of if POST goes through or not.

If you really HAVE to unplug the system before it will restart, you are either shorting out somewhere or the PSU thinks you are.

http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems

 

[FluffyWaffles]

I went through the checklist, lead me to believe my problems were (originally) a mixture of defective ram and motherboard. I have replaced both of the parts and everything now seems to be working perfectly fine. Never did occur to me that I possibly had two defective parts in my first build.

I will be keeping everything running stock until everything stays working for a month or so. Hopefully, this will be the end of my problems. Thanks for the help!