This dialog allows you to set the number of bits per code used for compression. It does not apply to already compressed files; these must be decompressed with the same number of bits as they were compressed with (handled automatically).
• More bits require more RAM, therefore if you are moving the compressed file to a machine with limited memory, you should set the bits parameter to something appropriate. Even a 512K Mac can deal with 16 bits/code, I believe, though I don't have one available for testing.
• More bits result in faster and greater compression than fewer bits.
MacCompress will dim the choices for which there is too little available memory.