No... that is what's odd. They are perfectly lined up in System Prefs > Display > Arrangement. From left to right they are in order when the computer starts up. Believe me i've done this a thousand times to make sure what i'm doing is right. My cabling and linking to the computer is correct. I can ...

Does Frame rate matter? I'm using 29.97 as a frame rate. I could drop it to 25, 24, 23.976 if that would make a difference.

Well... when I first fired up the MacPro it was on Lion 10.7.5 (sorry i said SnowLeopard, that was wrong) and it had a random upgrade to do so i did it. After that it was "chunky..." I previewed a file prior to that and it was fine.

I can't believe that small upgrade to Lion 10.7.5 was the problem ...

Ok, so this might be completely random but I upgraded to QuickTIme 7 PRO and suddenly most of the "chunky-ness" has gone away. It's not perfect - but considerably better.

Does that make any sense at all?

Yeah, it worked perfectly. Only thing I did was set it up, turn it on... there was a software update which I ran. That was an update to Snow Leopard OS - now it's running Lion OS.

I suppose I could restore or re-install Snow Leopard. But that doesn't seem to make sense.

Another odd thing is when ...

Ugh, the AIC video file would not run through ArraySync in safe mode.

It would run in Standard Mode perfectly. In Mirror Mode it was very chunky on the 4 monitors. In Spanned Mode it would not run at all.

This is really bizarre.

Yeah, ArraySync has worked perfectly prior to this video update. I'll try the safe boot and see what that produces. I tried a AIC file and received the same "chunky" results.

I did just update to Lion OS and ran a test and it still was "chunky"...

Video card drivers perhaps?

I use ArraySync to link up 4 40" NEC monitors together for a trade show wall for the company I work for. I create video files out of Adobe After Effects that are about 4-6 minutes long. I save them as AIC files or ProRes Proxy files. Typically the are 1-4 gig in size. The file size in pixels is ...