Hi all-
I built a new PC and have encountered some freezing. Symptoms include hard freezing: everything locks up, no input from keyboard/mouse, does not unfreeze and I have to restart with button. No sound occurs after the freeze. Can occur in intense gaming or even randomly when not, but it does happen more often when everything is being pushed. Nothing has been overclocked, running out of the box except for "downclocking" memory.

I previously had an ethernet issue (kept saying ""Ethernet" does not have a valid IP configuration" which was resolved by reinstall of Windows

Here is what I have done:

• Run Speedfan/HWMonitor/Overdrive to monitor temperatures/thermal margin before, after, and during freezes (no results; CPU not overheating even when taxed)
  
• Pushed to freeze using Prime95; again, nothing outside of normal parameters pushing the CPU/RAM
  
• Downgraded RAM (is "underclocked" a thing?) to 1866, the capacity the processor is supposed to be supportive of;
  
• Manually input voltages for RAM and all of those numbers (11-13-13-31)
  
• Run Memtest86 for 19hrs, and 4 passes; no faults found
  
• Switched memory to different slots, tried just using one stick at a time; no change
  
• Reseated everything
  
• Reapplied thermal paste
  
• Unplugged everything except keyboards/mouse, no additional peripherals
  
• Reinstalled Windows
  
• Run Samsung Magician to make sure my SSD was running optimally (it was)
  
• Checked on all drivers and made sure Windows and BIOS were up to date
  

2 examples of freezing temperatures/stats while using Prime95 push test:
http://i.imgur.com/bhq6CLC.jpg
http://i.imgur.com/5pQ7g9o.jpg

Here is my rig:
ASUS Crosshair V Formula-Z AM3+ AMD 990FX + SB950 8 x SATA 6Gb/s USB 3.0 ATX AMD Gaming Motherboard with 3-Way

AMD FX-9590 Vishera 4.7GHz Socket AM3+ 220W 8-Core Desktop Processor - Black Edition FD9590FHHKWOX with Liquid Cooling Kit

G.SKILL Sniper Series 16GB (2 x 8GB) 240-Pin DDR3 SDRAM DDR3 2400 (PC3 19200) Desktop Memory Model F3-2400C11D-16GSR

ZOTAC ZT-90503-10P GeForce GTX 980 Ti AMP! 6GB 384-Bit GDDR5 PCI Express 3.0 SLI Support Video Card

SAMSUNG 850 EVO MZ-75E250B/AM 2.5" 250GB SATA III 3-D Vertical Internal Solid State Drive (SSD)

EVGA SuperNOVA 1000 G2 80+ GOLD, 1000w Fully Modular NVIDIA SLI and Crossfire Ready 120-G2-1000-XR




I'm not sure what to do next; is the likely culprit after all of that a faulty mobo? What's the next course of action?
Any help would be appreciated.

Thanks!