Do i need the 32 bit or 64 bit version of Mysql for use with php 5.5
If your Mac is 64 bit, the 64-bit version would be preferred. If you are on a 32-bit system, you'll have no choice but to go with the 32-bit version. See the How to tell if your Intel-based Mac has a 32-bit or 64-bit processor to determine what you are running.