System Instability

[USF-Nealio]

I've recently put together a gaming rig/home workstation rig from some leftover parts, and I'm experiencing some rather odd instability.

Build Specs:
Core I5-750 w/stock cooler & stock clock
Asus Sabertooth 55i
8GB of RAM (forget the brand at this point)
74GB WD Raptor OS Drive
160GB Samsung Data Drive
Sunbeam Nuuo 550w Modular Power supply
Antec P180 case
Windows 7 Ultimate (Not activated, 25 days remaining)

Note: NO Optical drive at this point

After first booting for the day, the system will run perfectly for hours. After several hours have passed, (and usually when attempting to open a new program) applications will slowly become non-responsive over a period of a minute or 2 before hanging completely. After a forced reboot, it'll quickly do the same thing once windows has loaded. I have to turn off the rig for 30+ minutes before it'll start behaving again.

Tests completed:
Checkdisk on both drives, no errors found.
No S.M.A.R.T. errors detected.
Memtest86+, no errors found.
Prime95 for 8 hours, no errors found.
PSU voltages are normal when connected to PSU tester

Temperatures:
CoreTemp: All 4 cores are >45*C at any given time.
Speedfan: Slightly confusing. There are 6 different CPU temperatures.

Current Temps:
1. CPU on Winbond W83667HG-B reads 37*C
2. CPU on ATK0110 reads 43*C
3. Core 0-4 read 33-37*C

I understand that the Winbond is just displaying the maximum temeprature for the 4 cores, but what is the ATK0110 reading? It's always 6-10 degrees hotter than any other CPU value.​

I plan to grab my Multi-Meter from work to test the rails while under load. What else should I look into? I figured I'll image the hard drive to an external drive and then attempt to repair the windows installation in a brute force attempt to fix it.

 

[Sn0_Man]

I'm not an expert at all, but it sounds a bit like maybe your RAM overheats? Then if you leave it shut down for 30 mins it cools and you are good?

Thats my best guess. If you figure out what kind of RAM and what timings that might help. Also, how is ventilation in your case?

 

[USF-Nealio]

I hadn't thought of ram overheating. It's Patriot G2 with heat sinks. I have 4 120mm case fans. 2 on the front pull air into the case, 1 on the rear blowing out, and 1 at the rear of the top blowing out. 3 out of the 4 are set to 3 speed switchable, and I currently have them set to medium. The 4th is connected and controlled by the motherboard. The power-supply actually came with a small fan controller, and it is currently only controlling the fan in the power supply. The motherboard has a provision to install a RAM fan (40/50mm), so I'll probably do that for kicks. I am trying to pick-up an AIO Watercooling loop and mount it in a manor that would directly expell the CPU heat outside of the case (probably by mounting it to the top 120mm fan hole).

 

[Dangman]

Try using the HDD manufacturer's testing software to test the hard drives.
Try a different PSU if possible.

What's the model number of that RAM?

 

[larrymoencurly]

I hadn't thought of ram overheating. It's Patriot G2 with heat sinks.

Oh-oh.

What I mean by that is, RAM made with heatsinks often contains no-name chips or chips that are overclocked, and you can't tell without voiding the warranty. Also the testing that most makers of retail modules perform on their products isn't exactly thorough. But RAM doesn't overheat, which is why it never needs heatsinks.

MemTest86 and MemTest86+ often give different results.