multi-display problems... lagging, jerky displays - a workaround

I have a Mac Pro, early 2008, with three ATI Radeon 2600 XT adapters and six monitors of various pedigree. Presently running Snow Leopard, 10.6.8 but have been seeing this problem for quite some time, over multiple OS releases.

I have been experiencing this problem consistently for many months, but I've been unable to really characterize it, so I didn't want to say anything.

Today, however, Googling in great frustration, I did find some other comments, and a workaround; which seems to be working, and also appears to point at the culprit.

Basically what happens is that if I leave an application on a display busily redrawing -- doesn't matter what the application is, or whichy display it is on, only that it's regularly / steadily updating its display somehow -- that app will begin to lag redisplay, stop for a few moments, pick up again and then lag again... and one CPU core shows 100% while this is happening. However, the app is not any busier than usual. It will behave for a few minutes (usually) if I put the mouse pointer over there and wiggle the application window's title bar. Which is ridiculous, of course.

I see this on chat applications, software defined radio applications, games and continuous animations, videos, etc. Basically anything with a display that stays busy.

So, the workaround is to set all the monitor profiles the same; I have a profile called "Display" that was available on all monitors. I applied it to all six of them, and then -- magically, as Apple would have it, lol -- the lagging and jittering goes away, apps display smoothly all day long. For which I am profoundly grateful, but now, of course, the individual monitor colors aren't great.

So it would appear that the color profile processing is broken, actually quite badly.

I found that people with VirtualBox are seeing it and fix it this way (that's where I found the workaround.)

So... anyone else experiencing these kinds of lags / jitter / refresh / redraw failures with multiple monitors? Does the workaround I describe work for you?

And... how can I / we get Apple to address this?

TIA