SETUP: I have an late 2007 mac pro dual quad core 3Ghx originally with the noisy ATI X1900 running two monitors (a 20" and a 30"). Current setup: Bays 1 & 2 RAID 0 Main boot partition ~1.4 TB RAID 0 Scratch Partition 32 GB Bay 3 BKUP Disk 1 (1.5 TB) Bay 4 BKUP Disk 2 alternate (1.5 TB) SuperDuper used for disk imaging on Disk 3 and 4 alternating. Objective: Maximize perfomance on Aperture and CS3 -added 8 GB RAM to 16GB -added ATI3870 (PC and MAC edition) -added NEC2690WUXi monitor. -note: had to upgrade from Tiger to Leopard (ATI3870 not compatible with Tiger). PROBLEM: - When running Aperture editing software the apps crash (not system) -can't get three monitors to work together. The displays on one or two out of the three monitors show either blacked out quadrants, or unreadable scrambled images. -System Preferences dialogs that run on all three monitors such as Monitors, will show scrambled pixelated unreadable garbage in the box on one or two of the monitors TROUBLESHOOTING: -firmware BOOTROM and EFI are both up to date -X1900 Firmware updated to latest -All apple updates applied to latest (leopard, all security updates etc) -All software updates applied (Adobe CS3, Aperture etc to latest versions) - Disk Utility and Disk Genius checked the disks, -reinstalled everything (twice) - reinstallied Leopard first with archive-install, then clean install -tried every conceivable combination of monitor to video card I have NOT had any success. I spoke with ATI a couple of times, the last time today I got an escalation to a senior tech who told me that the power supply is probably the problem?? NOTE: run TWO monitors out of ONE card, it works OK. QUESTION: Should I try to find a better power supply? Is it possible that the MAC PRO standard power supply is not sufficient to power up both video cards at the same time? Should I just trade out the power hungry X1900 for a less power hungry 2600? There must be hundreds of people who use 3 monitors and ATI video cards without all these headaches? What setup did you use? Thanks in advance to anyone who can give me some advice on how to fix this. Not sure what to try next!