I've noticed that the longer i have had Max4Live running , the longer it takes to copy objects. If i copy a large number, say 50 menu objects, it can take over a minute to copy them, and max doesnt respond until they are copied.
I noticed this problem previously with the stand alone version of Max MSP. I have to keep restarting the program, or it takes a long time to copy even a couple of objects.
2.4 Ghz Intel Core 2 Duo