05-29-2015, 06:25 PM
A number of MBPs from that era (though it's more common in 2008-2010 models) have a SATA cable which is not "good" enough to handle the full speed SATA throughput of an SSD but are OK for HDD use. This seems strange but our hardware guy here has done dozens of replacements to fix this problem.
The difference here is that we noticed this problem when swapping out an HD for an SSD and that's when the problems start. Pop in a replacement cable (~$20) and all is well. Since your SSD was working well in the machine beforehand, perhaps this is not the case. It's also hard to test this without other known good cables lying around (I have a 15" MPB5,3 cable on my desk here awaiting another flaky SSD upgrade).
The difference here is that we noticed this problem when swapping out an HD for an SSD and that's when the problems start. Pop in a replacement cable (~$20) and all is well. Since your SSD was working well in the machine beforehand, perhaps this is not the case. It's also hard to test this without other known good cables lying around (I have a 15" MPB5,3 cable on my desk here awaiting another flaky SSD upgrade).