I have been frequently getting CTDs playing the 0.63 Experimental, the only time it seems to occur is when I am interacting with my inventory(opening, closing, moving something from the "Vicinity" window to a container or moving items within a container) and I receive the following message :
"The instruction at 0x3ff0cee3 referenced memory at 0x0000004b. The memory could not be read. Click on OK to terminate the program. Click on CANCEL to debug the program."
Basically just opening the inventory, moving things between the "Vicinity" window and the inventory containers. Combining items to perform actions in the inventory, etc.
It does seem that the crashes are more frequent on higher population servers, and that they occur more often when loading/unloading magazines, crafting, or any other actions which alter/create/remove items.
There isn't much else that I can tell about the issue, it seems to just occur at random with no warning signs prior to the crashes. The game runs very smoothly and plays well over all, this issue is the one thing that is keeping me from wanting to play all the time.