Crossfire/Second Graphics Card Issues

darkopia · September 1, 2015

Below i have outlined some of the parts in my PC

PowerColor R9 270X TurboDuo OC 2GB GDDR5 DVI HDMI DisplayPort PCI-E Graphics card

MSI R9 270X GAMING 2GB GDDR5 Dual DVI HDMI DisplayPort PCI-E Graphics Card

Asus Sabertooth 990FX AMD 990FX (Socket AM3+) DDR3 Motherboard

AMD Bulldozer FX-8 Eight Core 8120@8150 Black Edition 3.60Ghz (Socket AM3+) Processor

OCZ Fatality 750W modular power supply.

2 * 27" 2k displays using full dvi 2560*1440

I am running on windows 10 64bit but had the same issue on windows 8 and 8.1. I have been just living with this for a couple of months but I would really like to find a solution or an explanation as to why this is happening.

The reason I opted to go crossfire is that I was hoping that it would help with the noticable lag I get in games and watching vidoes etc which is driven out of powering the 2k displays. (i assume)

I have tried a number of things already as you can imagine and I can't understand whats causing it.

Both cards work perfectly when alone however as soon as I install the second card, one of them will drop to 300mhz base and 450mhz when active clock speed and 150mhz memory leaving only one card working properly. if I split the monitors between the two cards the same thing happens and one screen will suffer. The cards also will not recognise a crossfire which I would assume is related to the issue.

I have tried the cards in different PCIE slots and the same effect occurs. Either card will run fine in any PCIE slot as long as it is alone.

Not sure what else to try of if something is faulty or not supported. Any help would be appreciated.

Many thanks