Run 6 monitor display on Dell T110

Hi all, We got a new 6 monitor display for our operations group. I wanted to reuse a Dell T110 I have to drive the displays. There is 8Gb of memory installed on the server and Windows 2008 R2 64 bit is the OS. I bought and installed two new ATI graphics cards - ATI Firepro MV 2460. (4 DVI). - in Slot 2 ATI Firepro 2270 (2 DVI) - in Slot 3 Either card works ok on it's own, but when both installed together I get a Code 12 Device Cannot Find Enough Resources which knocks out the 2460 card. I have updated bios and all related drivers to latest level including ATI drivers for the graphics cards. For now I have removed the 2270 card and am just driving 4 of the 6 monitors off the 2460 card and all working ok with this. Anyone got any ideas on how to get around this code 12 device error ? or is this just too much for the T110 ? Thanks.