Dual Displays Not Working Properly

I have 2 monitors hooked up to my Mac Pro 5,1. Both are connected via VGA to the ATI Radeon HD 5770 via a VGA->DVI converted and a VGA->Mini DisplayPort converter.

One monitor is a 4:3, 1280x1024 native resolution, and this works fine whether it is connected with the DVI converter or MDP, and works whether the other monitor is connected or not.

The second monitor is a 16:9, 1920x1080 native resolution monitor, and will only register as connected if it is connected via the VGA->DVI connecter. It receives the signal whether the other monitor is plugged in or not, but if the 4:3 monitor is connected, it squeezes the 1920x1080 signal and puts black bars on either side of the image (it fills the screen properly when the 4:3 monitor is not connected).

Also, when the computer first boots up, it never recognizes the 16:9 monitor (regardless of input), and I must unplug them and plug them back in to get them recognized.

I have tried all the standard troubleshooting, switching cables, resetting PRAM / NVRAM, flushing power from the tower, etc. Any ideas are welcome!

Thanks!

Here's the hardware info:

OS 10.6.8

Mac Pro 5,1

2 x 2.66 GHz 6-Core Intel Xeon

6 GB RAM

ATI Radeon HD 5770

Monitor #1

NEC AccuSync LCD93vx

(1280x1024 @ 60 Hz)

Monitor #2

Samsung SyncMaster SA200

(1920x1080 @ 60 Hz)

Message was edited by: JNorris09 - Corrected description of aspect ratio of 2nd monitor (19:9 -> 16:9)