I have a Mac Pro 2009 built-in 980w PSU, and a MSI R9 390x, but there is one problem. My psu has worked fine with the old graphics card I had, but this new one makes my computer shut off whenever its power usage gets high. I can't start a game like ACS, ArmA 3, or Warframe, without it crashing. My card works fine as it can render my desktop and more perfectly, but crashes in any power-hungry situation. I tried using MSI afterburner to see what voltage it can get to before shorting out, and the answer was 1200 mV. My PSU can support 980 Watts, so I'm not exactly sure what that converts to, but I know the graphics card requires around 500 Watts, so I'm just not sure why this isn't working. My PSU and Graphics card work, just not together when i play a demanding game. Please help, Thanks -Ted
EDIT: Even going 15 seconds on a youtube video makes it crash.