Is there a way to tell if I can use a SATA III SSD in my early 2011 MBP 15"? I put my MBP next to the new Retina MBP today, and although the new display was incredibly crisp, and normal usage distance, it's just not that much better than mine as I'd opted for the high res (1680x1050) display. I'd thought I could for a lot more on the display, but it's not enough of a difference to justify cost, so I'm sticking with this, and going to upgrade the HDD to SSD instead.

I've heard that some of the early 2011 SandyBridge models had a problem with the SATA controller and that they didn't actually support SATA III.

Is there a way to check this out without actually just installing one to see if it works?

Intel 6 Series Chipset:

Vendor:   Intel
  Product:  6 Series Chipset
  Link Speed:   6 Gigabit
  Negotiated Link Speed:    3 Gigabit
  Description:  AHCI Version 1.30 Supported

I see from the system info that it has a 6gb link speed, but obviously the standard HDD is only SATA II, other than that I'm at a loss to see how to tell.

Any ideas?
I have the low-end MBP 15'' early 2011.

It has a SATA3 interface. As I have a SSD build-in, the negotiated link speed is 6Gb/s as well. Benchmarks achieve speeds of up to 510 MB/s, which is clearly SATA3.

Also, make sure that you have the latest firmware installed. The early 2011 MBP received firmware updates which enabled full link speed (as of revision 2.2).