Kernel Panics on Mac Pro 2009 while playing Video

I seem to be getting Kernel panics randomly. This time it occurred while playing back SD video. I drive four monitors*in portrait mode with two NVIDIA GT120 graphics cards. The system is running the latest version of Mountain Lion which does not work well with Portrait monitors [LINK]. When I reboot the system, the displays must be rearranged or sometimes, one or two of the displays are blank.

NOTE: It always happens when the graphics card is being used intensively, playing back video (within hours) or Photoshop (within a few minutes).

Most of the time, the system is just fine. I keep the machine operating 24/7 and need near 100% reliability, could one of the cards be failing? I purchased the second GT120 card from someone selling it locally just over a month ago. Or is it the same "portrait monitor blank screen" issue as others are also having Kernel Panics.

Attached is a KP log. Below is an excerpt from the log. Going back to Lion on a different drive for now.

Code:

Interval Since Last Panic Report:  466755 sec
Panics Since Last Report:          1

      Kernel Extensions in backtrace:
         com.apple.NVDAResman(8.1)[A26D2A3D-C06F-3A0F-BCFF-901A98C93C3D]@0xffffff7f8fdd3000->0xffffff7f900e0fff
            dependency: com.apple.iokit.IOPCIFamily(2.7.3)[1D668879-BEF8-3C58-ABFE-FAC6B3E9A292]@0xffffff7f8fccc000
            dependency: com.apple.iokit.IONDRVSupport(2.3.7)[38C214C0-83C8-3594-8A4C-DC6AC3FEC163]@0xffffff7f8fdbf000
            dependency: com.apple.iokit.IOGraphicsFamily(2.3.7)[74E3E50F-E50A-3073-8C96-06F854292A91]@0xffffff7f8fd7c000
         com.apple.GeForce(8.1)[A15BB65E-3501-340F-87CB-2FD2BAD33E35]@0xffffff7f90b6c000->0xffffff7f90c38fff
            dependency: com.apple.NVDAResman(8.1.0)[A26D2A3D-C06F-3A0F-BCFF-901A98C93C3D]@0xffffff7f8fdd3000
            dependency: com.apple.iokit.IONDRVSupport(2.3.7)[38C214C0-83C8-3594-8A4C-DC6AC3FEC163]@0xffffff7f8fdbf000
            dependency: com.apple.iokit.IOPCIFamily(2.7.3)[1D668879-BEF8-3C58-ABFE-FAC6B3E9A292]@0xffffff7f8fccc000
            dependency: com.apple.iokit.IOGraphicsFamily(2.3.7)[74E3E50F-E50A-3073-8C96-06F854292A91]@0xffffff7f8fd7c000

BSD process name corresponding to current thread: Finder

Mac OS version:
12D78

Kernel version:
Darwin Kernel Version 12.3.0: Sun Jan  6 22:37:10 PST 2013; root:xnu-2050.22.13~1/RELEASE_X86_64
Kernel UUID: 3EB7D8A7-C2D3-32EC-80F4-AB37D61492C6
Kernel slide:     0x000000000f400000
Kernel text base: 0xffffff800f600000
System model name: MacPro4,1 (Mac-F221BEC8)

System uptime in nanoseconds: 185527221598496

 

I drive 4 monitors, experiencing strange behaviour since Lion 10.7.5... That's the build in which drivers made by NVIDIA are included. Anything below works just fine.

I sold off my GTX 670 because I felt that it was overkill for documents, film scripts and image/poster creation. The GT120's work just fine except for the kernel panics.

Looks like the only other working options I have are:
- Use Lion 10.7.4 temporarily
- Get a Quad Monitor Stand and use displays in Landscape (expensive).
- Sell all displays and get two u2711 or u3011 (hard to find a buyer).