I've noticed in the last couple of months that no matter what, my mouse seems to lag when the cursor is on the external display as opposed to my MBP where it seems more accurate. There seems to be a slight lag, especially when making bigger circles in a fast motion with the cursor. I've tried to use the Steermouse App with limited success. It's better, but not great. The mouse is a Logitech VX Revolution, and the display is an NEC LCD2490WUXi. I've also noticed the same issue when using an HP 24". It kind of makes editing a pain to be honest, especially with shaping masks and such. Anyone have a similar issue or solution? I tried to hook up my girlfriends little tiny Microsoft USB corded notebook mouse, but the same thing occurs. At work we use a Mac Pro and a G5, both hooked up to 22"ish Dell displays using a corded Apple mouse, and there is no lag at all...dead accurate and a pleasure to work with. This is just....annoying to say the least! I should also mention that I've tried multiple USB ports and locations for the reciever, all unobstructed and fresh batteries. Tried the MBP USB ports, the Belkin powered hub I use, and even the side of my Apple wired keyboard. All the same. I've also noticed this on both my 15" Penryn and my new 15" UMBP.