Dual Monitor Glitch
 

Perhaps this has been mentioned somewhere before, but today I discovered a problem while trying to run off a cloned hard drive.
Before upgrading to Leopard last week, I made one final back-up of my Tiger system with a complete copy to an external drive. After realizing I had some apps that no longer work in Leopard, I decided to boot up from my external Tiger disk and work off of that for a while. I usually work in a dual monitor setup, but the boot was slow and the second monitor displayed erratic images. Further everything worked extremely sloooow to the point of uselessness (like 2 min. to select a menu item). I figured the second monitor was the culprit, so disconnected it, rebooted and things work smoothly,though I would like to have that second monitor function. I get the same results when booting from a second internal drive which also has a clone with Tiger, although not as up-to-date as my external drive.
So is this a problem with SD's backup or something internal with my Mac?

Using a 2.66 Dual-Core Ontel MacPro w/ 2 GB ram

I use two monitors and haven't seen anything like that, JTD. Anyone?