Quick question about upgrading RAM and SSD

@danj Not doubting you at all (you know much much more than I do about Mac repairs), I guess I am still confused. When I check the system specs on everymac it tells me the "storage interface" is Serial ATA (6 Gb/s) and when I click on that, I get this expanded message "This model supports a single SATA III (6 Gb/s) 2.5" hard drive or SSD that is up to 9.5 mm thick." Does this mean I have the SATA III cable already or its just the maximum I can have in the system?

My SATA system report also shows I have Intel 6 series chipset with a Link Speed of 6 GB/s and a Negotiated Link Speed of 3.0 GB/s. I was under the impression that meant it could support a 6 GB/s drive natively and the negotiated link speed was the speed the current HDD could handle.

Thanks again Dan!

EveryMac is Correct! the system does have a SATA III (6.0 Gb/s) interface! And yes what your system is reporting is correct!

Lets get into the wayback machine!

Its now the end of 2010 you are in design review meeting at Apple, the last one before going into production. You are the person responsible for the drive subsystem and you have some bad news to share with the group. The suppliers are unwilling to commit to the quantity of drives Apple needs at the price Apple is willing to pay and the first version of the SATA ribbon cable is not going well as it's not able to run at the higher SATA III data rate. So Steve tells you lets just go with the SATA II drives and when we need to re-contract the drives we'll hit them up then for the faster drive and for now use the cables we have.

A few moths later Apple released a newer cable and turned on SATA III services within the systems firmware Apple was still was using SATA II drives (the last build of the early systems did get the SATA III drives and the late 2011 models did as well).

But, Apple still had a crappy SATA cable it wasn't until the 2012 systems came out did they get it to work flawlessly at full SATA III data rates. You see SSD's can push more data than what the older cable can support and HDD's didn't push the limit so it was possible for them to get away with using the crappy cable (gen2).

@danj awesome thats very informative thanks Dan! So to clarify, technically yes the current cable could be connected to a SATA III drive, it just simply wouldn't push the same speeds as the newer cable and would defeat the purpose of a faster drive, is that more or less correct?

That's a good summary. To come back to one brief issue: it's critically important NOT to crease the cable. It makes the stranded copper fibers inside of the cable crack and break; while they may remain in contact at first, eventually they will corrode and/or migrate, causing the cable to degrade and fail.

@urbs_ - The ability of the drive and the ability of the system is limited by the cable connecting them. You will encounter CRC errors which will create corruptions on the drive and cause your system to overheat (a damaged cable will likewise cause these errors)

Yes! David, You are correct damaging the cable is a common issue! This ribbon cables are in fact foil not braided wires. Just like how a paperclip fatigues when you bend it a few times the foil conductors likewise get damaged from the creasing or when you over bend the cable.