This issue dates back to when I first bought one of the (Early-2011) 17" MacBook Pro's and has been a thorn in my eye ever since. By "the issue", I mean the faulty SATA III (6Gbps) implementation in the 15" and 17" MacBook Pro's. Curiously enough, the 13" MBP's, both the (Early-2011) as well as the (Late-2011) work just fine with SATA III in all bays!
I have been through a 15" (Early-2011) MBP and when the (Late-2011) MBP's came out, I thought "Finally! Apple must have fixed it at long last" and I immediately upgraded to a 17" (LATE-2011) MBP (still MBP 8,3 identifier, by the way), but referred to as (Late-2011) MBP by Apple itself.
Unfortunately, after numerous EFI updates as well as other software updates, both the 15" and 17" models still do not work correctly as far as operating a SATA III (6Gbps) in the optical drive bay! After a lengthy conversation with Tech Support, and because I wanted to go back to a 17" MBP, I went all out and bought the "anti-glare" model and the only anti-glare (matte display) model that they carry in the Retail stores conveniently only comes upgraded to the higher CPU and yet another $50 to get a 7200rpm drive instead of a 5400rpm one. Fine by me I thought, even though the first thing I would do was to take out the hard drive and put a SATA III SSD into the hard drive bay. Thing is, I have two of the OWC Mercury EXTREME Pro SATA III SSD's and the second one goes into the optical drive bay, and after using Apple's software RAID 2.0, which works great, by the way, I usually get upwards of 900MB/s (and over 100,000 IOPS) in any Mac mini, and strangely enough, this works just fine in the 13" (Early as well as Late-2011) MacBook Pro's.
That's right, perhaps the most infuriating part is the fact that the 13" MBP works just fine with SATA III SSD's in *both* bays! Why wouldn't it? They're both SATA revision 3.0 bays on Intel's 6 series chipset. Incidentally, yes, I do realize that Apple not only has never advertised the fact that SATA III drives can be used since its (Early-2011) MBP models, but they haven't even so much as mentioned it in any of its marketing materials either, but that's no excuse. Tech Support (AppleCare) is fully aware of this issue and they keep promising me that it will be fixed "...in the next firmware update".
So...what do you think? Is there a "third-party" fix that I don't know about or perhaps the SATA cable running from the optical drive is improperly shielded?
Thanks for reading this and I know this is not an "everyday" issue, but I know that I'm not the only one who is affected by this.