I've just gone a built a new desktop pc and everything is working fine apart from when I put the graphics card under high stress levels.
My system consists of:
MB; Asus Z87-K
CPU; i5-4670K (overclocked to 4.4GHz)
Graphics unit; XFX R9 290 Boost Edition
RAM; 8GB Corsair 1600mHz
PSU; Andyson AD-E850AE-A5/A6
OS; Windows 8.1 64x
Every time I run a program which requires any hard work form the graphics card, the system restarts and notifies me that a power surge was detected in the last session, and so the anti-power surge system kicked in and shut down the computer. I have run burn tests on the CPU using Prime 95, and the system handled it fine, I've also manually turned the graphics cards fan up to 100% and the system didn't crash. However, when attempting a GPU burn using MSI Kombuster, the system lasts for about 5/6 seconds and then shuts down. When attempting to run World of Tanks on high graphics, the system shuts down instantly. I have updated the Bios to the latest version via the Asus website and the problem persists.
More about :asus z87 xfx 290 anti power surge restarts
My solution was very simple.
I did use the 8pin cable that came with the card (the one combining to inputs to one output). After some research everything pointed to the PSU, that's when I realized that it had specific outputs for the PCIe cards (2 6pins and 2 8pins). I already used the 6 pin so I decided to use the 8pin too.
Voilá, everything works
If you don't have those outputs marked, make sure that you use the corresponding outputs of the PSU with the correct Voltage.