I'm trying to get 5 monitors running off two ATI Radeon 5570 cards - 3 off the primary and two off the secondary. Both cards have 1xHDMI, 1xDP and 1xDVI. I am using the open source driver.
I can get three monitors running off the primary card, and the 4th monitor (DVI) running off the secondary card. I am using the display applet in Gnome3 to configure the displays. The OS is Linux Mint 15.
The problem is when I enable the 5th screen (tried HDMI, DP->HDMI, DP->DVI). The 4th and 5th screens become mirrored. And every time the mouse is moved any windows on those screens flicker (I assume it's redrawing the shadows or something). Video performance on the primary card is also affected.
Are there any configuration settings that can be modified, or is this a limitation of the open source driver? Where does the Displays applet store it's configuration for X?
I have tried to use fglrx and fglrx-updates from the Driver Manager that comes with linux mint, then used
amdcccle to try to wrangle the monitors into place but the monitor placement and multi-display options leave much to be desired. I could only get one screen usable and 5 blank screens (multiple "Single Desktop" monitors). Using "Multi Desktop" display makes windows expand across all monitors on that card, while separating the desktops between cards (so you can't drag windows between screens on different cards - WTF?).
Anyone have any ideas? Thanks.
EDIT: also tried an active DP-DVI converter on the 5th screen with no luck :(
EDIT: PSU is a 700W 80Plus Bronze CoolerMaster, but the cards have no AUX power on them. The motherboard however does have two AUX power plugs (Both SATA and Molex power types) of which the molex is plugged in. There is only a single SSD and DVD drive in it so shouldn't have too much load.