First off, I don't do a lot of modelling myself. I use Blender as a 3d object file tool when I need to compare my understanding of a file to someone else's. So I don't know how long this issue has been around, because I haven't done much in Blender in a long time.

I have two 1600x1200 LCD panels attached to my nVidia 5200, under Windows XP. Both are rotated. into portrait mode (so my combined total resolution is 2400x1600, because they sit side by side). Current nVidia driver version is 93.71, but this behavior was also present in the previous generation of driver (which is what I was running until I upgraded to try to fix this problem)

If I run Blender (have tried 2.42a and 2.43), various GUI pieces are slow to update:

- Menus do not appear until after the mouse has moved some distance (I'm guessing maybe about 5-10 mouse move events). This happens on all menus (the main menus, the spacebar menus, any of the special popups like pressing xKey to delete something, etc), and all the time.

- Sometimes (and only sometimes) views don't update to show selected items until the mouse moves over them.

- Trying to drag out a selection box with bKey is extremely painful, as the box lags the mouse (again by maybe 5-10 mouse move events). It isn't just slow, it actually never processes the last N mouse moves, so that to get the box where I want it, I have to wiggle the mouse at the final point until it catches up.

The "fix":
If I rotate my monitor back into landscape mode, the problems go away. I I rotate my monitor back into portrait mode, they come back. The problem is not wholly in the driver/OpenGL implementation, because I have been developing an OpenGL-based object manipulation program on this system, and have not had any of these issues myself.

Mac