Second 280x causes no post

Evan Bart

Reputable
May 21, 2015
3
0
4,510
My set up:
ASRock Z75 Pro 3
i7-3770
6gb RAM
Thermaltake TR2 RX 750W PSU
Sapphire Vapor-X R9 280x
Trying to add a PowerColor TurboDuo AXR9 280X

The cards work great alone. I played Skyrim on each.
I was missing a power cable and when it came in I set them up to crossfire.
When I turned on my machine it would hang at post and restart continuously.
I have downloaded and flashed my BIOS with the latest drivers from ASROCK and I have re-installed my AMD drivers.

Is this possibly a power issue?
I have 3 HDDs and a SSD installed, no disk drive and I have a USB 3.0 PCI card installed.
 

SBMfromLA

Distinguished
Here is the info for that particular card:

750 Watt Power Supply is required.
1000WattPower Supply is recommended for CrossFireX System.
2x150 Watt 8-pin PCI Express power connector is required.
4x150 Watt 8-pin PCI Express power connector is required for CrossFireX system.