Shutdown with no apparent reason
Motherboard model: ASUS Rampage V Extreme
UEFI Version: 1701, Bios 3202
CPU: Intel Core I7-6800K
Memory kit part number (s) and amount in GB: 8 – 64GB (KINGSTON HX426C15BK4/32)
GPU: AMD Radeon 6700
SSD/HDDs/Optical drives: ROG RAIDR PCIE 240GB, Seagate 3TB, 2 x LITEON BR writers
PSU: Corsair AX1200i
USB Devices (model/version number): Generic keyboard, Wireless mouse
Monitor: Viewsonic VA2238
CPU Cooler: ID Cooler 240mm Closed loop Water cooler
PC CASE: Corsair 900D
Operating system: Microsoft Activated yes/no? Install not possible (see Issues)
Drivers Installed (include version): As Above
Any third Party temp/voltage software installed: No
System Overclocked (provide details)?No
Issue
Purchased and built on 21/07/2016
System boots up, Monitor wakes and runs through bios, loads windows installer and starts install.
CPU Temp 25 deg. Full GUI. Mouse, Keyboard operational. Shutdown for no apparent reason.
Tried BIOS 1 and 2, Time before shutdown reduced from 5 Minutes to under 1 minute on subsequent tests.
Left idle or overnight and time increased on first start then dropped.
Actions taken:
Removed all but 1 stick of RAM with no change, swapped RAM stick, no change.
Used Known good PSU 750W Thermaltake Toughpower, no change.
Removed CPU & checked for bent pins or heat damage. None found. Reinstalled and retested with same results.
Unplugged power switch after start to eliminate faulty switch. no change.
Plugged PSU comms (C-link) into another computer and found no issues.
PSU runs Gigabyte M/b graphics and PCI SSD all day with no problems.
Removed from case and benchtested, PSU, Graphics, HDD 3TB, ODD. No Changes.
Any help is appreciated, thinking it is a RMA.