SSD Upgrade, only getting 3 GBit SATA Link Speed
Last night I upgraded a customer's 2012 MacBook Pro with a Samsung 850 SSD drive. An upgrade I've done a million times. I also replaced the hard drive cable with a brand new one (from ifixit!). Everything went fine with one catch. While the computer shows it is capable of 6 Gigabit SATA speed, it's showing it's only connected to the SDD at 3 Gigabit speeds. On drives this fast, that speed difference is extremely noticeable.
I have no idea why it would be using this slower link speed. Any ideas?