I just swapped from a HD 6950 OC'd with shaders unlocked to a r9 280x. Computer runs fine for destop, browsing, movies, and low demand games. As soon as you load the GPU in more demanding scenarios the computer stops responding completely… have to hard shut down. It continues to display a black or grey striped signal to my monitor. All fans and lights remain running as normal in the case. Tried reseating the GPU and connectors, and going to a different driver version. Temps appear to be fine for what I can gather before the shutdown (I tried a custom fan profile with high rpm with the same results). Uninstalled drivers and cleaned before installing the new GPU. Specs are as per sig.
Am I missing something. I am thinking it is the GPU or the PSU, but hope its not either. Any ideas? Any way to tell if its one or the other? The PSU is not the best, but less than a year old and should easily power the GPU