Iraklis Pazios
Bronze Level Poster
Yeah I also have a feeling it may be the PSU. But...I dunno.You mean RMA it again, right? According to him, PCS has already changed his motherboard, so how come he has another bad GPU??
I think it could be a PSU issue? When on battery it should work well for a while because it might be using the battery to provide full power to the system, since the PSU has some issue?
If you're going to RMA it again, make sure that they use your own PSU this time.