Computer Issue - What component at fault? CPU, power supply, RAM...?

[serotoninzero]

Short version of the story -

Computer won't run. Sometimes doesn't boot far enough to turn on displays, Windows starts up with errors, programs won't run 90% of restarts, tested power supply with multimeter and it's in range while not under load. Processor tested in Prime95 showed one core only completed three tests while others completed hundreds over course of ten hours; however no errors were found throughout test. Ram tested in MemTest86 and Windows Memory whatever showed no errors. Motherboard was recently replaced in hopes it would fix previous problems in boot issues. Worked better for two months. What's my issue? It seems like power supply to me despite my perfect voltage test.

Full story -

Two years ago I built a computer...

ASUS Crosshair III Formula AM3 AMD 790FX ATX AMD Motherboard
HIS H489FT1GP Radeon HD 4890 1GB 256-bit GDDR5 PCI Express 2.0 x16
OCZ ModXStream Pro 700W Modular High Performance Power Supply
AMD Phenom II X4 965 Black Edition Deneb 3.4GHz Socket AM3 140W Quad-Core Processor
G.SKILL 4GB DDR3 RAM Dual Channel Kit (x2 - 8GB total)

Six months later I upgraded with a SSD



OCZ Vertex LE (Limited Edition) OCZSSD2-1VTXLE50G 2.5" 50GB.

About a year ago it started acting up a bit... and seemed to get worse as time went on. It stopped booting instantaneously when I had any USB HDDs connected. Eventually it got to the point that I would have to unplug them completely in order for it to boot. Literal difference from twenty seconds to three or four minutes hanging on POST when a USB drive was plugged in.


I dealt with it because it didn't cause any trouble besides on boot, and I honestly don't reboot my computer often.


A few months ago, I upgraded my SSD and graphics card.


OCZ Agility 3 AGT3-25SAT3-120G 2.5" 120GB SATA III SSD
SAPPHIRE Radeon HD 6970 2GB 256-bit GDDR5

I had reinstalled Windows 7 at least four times over the course of my computer at this point. It ran great for a while, but then one day my computer would not boot at all. After removing my three other SATA HDD drives and my SATA DVD drive, it boot instantly. At this point, I assumed my motherboard was to blame at this point and I replaced it with this one:

GIGABYTE GA-990XA-UD3 AM3+ AMD 990X SATA 6Gb/s USB 3.0 ATX AMD Motherboard

I only threw money at it instead of fully troubleshooting because I was already interested in upgrading to USB 3.0 and SATA III as well. I still feel my processor is great and don't feel I need a new one at this point. Especially and unfortunately based on reviews on the FX series. System was running fine after the install in November. Skyrim ran 1080p, ultra settings, with more graphic tweaks almost flawlessly at all times. Suddenly while playing Skyrim it slowed to a crawl. I finally got it playable again by dropping my settings to medium, 1080p. Played more Skyrim for a couple days.

Two days ago, it turned on NS wouldn't allow me to do anything. Multiple programs wouldn't work at startup. One error stated that a certain .dll file wasn't for a Windows operating system. Another error said another thread could not be created. Explorer would not work. Downloaded MemTest86 on another computer and tested with no errors. After a few reboots I got it running and downloaded Prime95. Tested over the period of ten hours in a test that put more stress on CPU and less on RAM. Three of my cores averaged around the same amount (I think in the 300s?) of completed tests while another one only finished three in the whole test. When I stopped it, it didn't say that any errors were created throughout the test. I pulled the power supply this morning and tested it with a multimeter. All tests showed that the power supply was well within range. This was of course not under any load either.

So basically, what do you think the issue is? Do you think I'm running into power issues, RAM issues, or processor issues? Would one core failing cause all of these issues that I have been having with my computer? All three of them are still under warranty, but only if I send them an actual malfunctioning unit... so without buying new ones to test with, what's my problem?

Thanks for any input!

 

[tlmck]

I would say have the power supply tested locally if you have such a facility. If nothing else it will eliminate it as suspect. A lot of places will test for free at least where I live. It is a very good PSU, but even they fail on occasion. It could be a leaky capacitor that cannot hold it's charge. or a ticky voltage regulator. The good news is you bought a quality PSU that will shut itself down before destroying everything else you have.

The next would be the CPU. It is almost acting like a car with a faulty cylinder. The car will still run mostly, but not as well. Other than popping in a replacement, I cannot think of a better way to test than you have already done.