So I have recently bought a new GPU for my pc build, (AMD R9 290), fitted it and installed all the newest drivers since having fitted it the PC keeps on powering down and rebooting. Three times in one night etc. It's not under and load or at any specific point, can do it at idle it just seems to be completely random. Event log says this every time; "A fatal hardware error has occurred. Component: AMD Northbridge Error Source: Machine Check Exception Error Type: HyperTransport Watchdog Timeout Error Processor ID: 0" As the GPU was new and a big step up from previous I thought it could possibly be the PSU, so since bought a Corsair 850W psu (over specced) but wanted to make sure it would be okay. Error is still happening obviously. I have updated to the latest BIOS from the asus website. I have done a memory check using memtest 86 all fine. I have uninstalled and reinstalled the drivers for the GPU but still the same problem. Processor is AMD FX-4170 not over clocked, I just dont know what the problem could be. I was hoping if any of you guys could shed any light on it. Any response would be greatly appreciated, thank you in advance! (hope it all makes sense I have typed this quickly in fear of it rebooting haha!) Can upload the mini dumps if that will help. Thanks guys!