In the past, MetaX has had a problem when opening a large number of files and trying to tag them. The issue was with the amount of virtual storage required to store all the cover art. In the last couple of releases (V2.72 and V2.73) MetaX has reduced the amount of memory used to store the cover art, and added new functionality to monitor the problem. There is now a new preference on the General tab, Enable VM Checking that changes the behavior in a way that reduces the virtual memory usage. In the past, after MetaX tagged a file, it was left in the write queue, which means that the memory associated with the cover art was still being used. With VM Checking enabled, after the file is tagged, it is removed from the write queue, thus freeing up the virtual memory. Using this feature, I have been able to open and tag over 2000 files at one time.

To help protect from file corruption, if more than 1500 files are opened at once VM Checking is automatically enabled.