Makus is right but here's what you want:

1st Get the largest/fastest internal SSD DRIVE you can afford, for your OS and PT.(Up to 100,000 IOPS 4k Random Read Up to 95,000 IOPS 4k Random Write the higher thease #'s are the faster it is)

2nd Max out your ram (put your Mac Book Pro model # in at Everymac and it will tell you what type ram and what it can be maxed out to, however my Mac Book Pro: said 6gb ram and I successfully run 8gb ram and a TerraByte Hard drive) this will give it a shot in the but!!!

3rd get the largest external drive (this is a USB if you have a Thunderbolt or Firewire port you may want to get a drive that has it) you can afford and use it for your data drive ei: all pt sessions, charts and everything.

The 2 drive set up is what PT suggests that you use. Keep in mind these are just suggestions of devices and you can spend much more or less according to your wallet. post your model and I will help you get started.