Not in need of anything this post, just thought I'd share with the fact that I have been at the office this Saturday getting some overtime, and I haven't had one single lockup in six hours. I took RobertB's advice from another post and started using the MEP Basic 2-Line Display Representation instead of the MEP Design and wow. Not a single lockup. I guess the "hidden line" part really does kill the program's ability to maintain stability.
I wonder if I'm speaking too soon but I run a dual monitor setup with my AutoCAD interface spanned across both monitors with 2 vertical viewports, left in Plan View and the right in a 3D Model view with Realistic visual style applied for this particular BIM job we're doing. I usually get something to cause MEP to crash (uloading/reloading 3D XREF's, Orbiting around, moving around, etc...) but since I've made this change - nada. It doesn't seem like it's really any faster per se, but more efficient for sure.
I have to say I'm impressed so far but I really think that did the trick. I have been moving faster and pushing AutoCAD more than I usually do since I haven't seen any crashes. Still ticking strong.
Just thought I'd share.