What speed is the SATA controller in a medio 2010 Macbook Pro
You can find the speed of your SATA controller with the System Information application, by clicking system report &gt; hardware &gt; Serial ATA. Which in my case (a 15" 2.53GHz 2010 MBP) shows the following:

Intel 5 Series Chipset:

  Vendor:                   Intel
  Product:                  5 Series Chipset
  Link Speed:               3 Gigabit
  Negotiated Link Speed:    3 Gigabit
  Description:              AHCI Version 1.30 Supported


3 Gigabit means the maximum uncoded transfer rate is 2.4 Gbit/s or about 300MB/s (286MiB/s).

In conclusion: a 500MB/s disk is probably overkill.