New PC rebooting/freezing under stress

Hey guys I recently (within the last 2 weeks) built a new computer and it has been rebooting and freezing on me whenever I try to use youtube or play games on steam.There have been no BSOD, the computer just freezes requiring a hard reset, or it will reboot itself. I have already run several stress tests including: Heavyload, Furmark, prime95, and metest86*. The computer did not crash during any of these tests. In addition I have been monitoring hardware temperatures using SpeedFan, so I do not suspect the rebooting/freezing is due to overheating. I have used a different power supply to see if that was the problem although it did not change anything. I have also completely updated my graphics drivers.

*I ran memtest on my computer and could not reach 7-8 passes. I could only complete 1 pass in 20 hours, which was horrifically slow, It was 'stuck' on test 13 (hammer test) for most of that time. I did not feel like running my computer 140+ hours to complete a stress test.


OS: Windows 8.1 64bit
Build:
Geforce GTX 970 graphics card
AMD FX-4350 quad core processor
Gigabyte 970A-UD3P motherboard
8GB of PNY ddr3 ram (1x 8GB stick)
Corsair CXM series 500W ATX 12V power supply
PNY 120GB SATA-III SSD
Western Digital Blue 1TB Hard Drive

-Was having problems with an old thread so I made this one.
 
Checked found multiple of the same error: event 41, Kernel-Power: The system has rebooted without cleanly shutting down first. This error could be cause if the system stopped responding, crashed, or lost power unexpectedly.
 
Those are POST(after) failure and logged upon restarting.
You want the log entry that immediately follows this one.
 
Here was the error I found immediately before the most recent crash:
Event 6008, Eventlog The previous system shutdown at 2:42:30 PM on ‎7/‎6/‎2015 was unexpected.
XML view:
- <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
- <System>
<Provider Name="EventLog" />
<EventID Qualifiers="32768">6008</EventID>
<Level>2</Level>
<Task>0</Task>
<Keywords>0x80000000000000</Keywords>
<TimeCreated SystemTime="2015-07-06T19:17:08.000000000Z" />
<EventRecordID>3454</EventRecordID>
<Channel>System</Channel>
<Computer>Drew</Computer>
<Security />
</System>
- <EventData>
<Data>2:42:30 PM</Data>
<Data>‎7/‎6/‎2015</Data>
<Data />
<Data />
<Data>4805</Data>
<Data />
<Data />
<Binary>DF070700010006000E002A001E005402DF0707000100060012002A001E005402600900003C000000010000006009000001000000B00400000100000000000000</Binary>
</EventData>
</Event>
 
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