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I bought a Samsung EVO 860 1tb SSD last fall to use in my MacBookPro (15”, late 2011), which is now dying, and now my iMac (27”, late 2012) needs a new HD, so I thought I would take this drive out of the MBP and use it in the iMac. I have the iFixit kit for iMac SSD installation, so the last step is confirming which SSD to use. Before installing, I wanted to do some testing using Black Magic Disk Speed Test, here are the results: iMac Fusion Drive (HDD+SSD): Write: 150-200mb/s Read: 250-400mb/s Samsung 860 EVO: Write: 30-50mb/s Read: 220mb/s So my question is, what’s going on here? It makes no sense at all that the fusion drive tests results are beating the pants off the EVO, which is giving worse results than just about any HD I can recall testing. I did test the speed via Thunderbolt 1 using Target Disk Mode, but also got similar results directly on the MBP that houses the EVO. The SSD is pretty full, would that have a drastic affect on the speed? Is this thing just bad? Thanks in advance for any help!
You will also see some issues with just swapping out your MacBook Pro HDD to SSD. As you didn’t tell us which model I can’t give you the needed steps to replace it and what will be needed. Update (04/27/2020) I only use Samsung SSD’s as they have a good track record and their performance is always at the top when you check the reviews. I think your testing has hit its limits with your MAcBook Pro as well with a bad GPU. Even still your number could be better if you replace the older HD SATA cable which has issues in this series. Apple’s original cable was only rated for SATA II (3.0 Gb/s) so when you use a high performance drive you can end up encountering performance issues as the cable just can’t support the higher throughput. To fix this we install a better HD SATA cable which is designed to support SATA III (6.0 Gb/s) drives MacBook Pro 15" Unibody (Mid 2012) Hard Drive Cable. We also need to help protect the cable from damage as Apple also encountered issues with the rough surface of the aluminum uppercase. Here we use a strip of electricians tape to protect the cable from wear Your Hard Drive Cable Is A Ticking Time Bomb The next thing we need to worry about is in the process of installing it we don’t damage the cable. The cable is made of thin foil wires which can be damaged when you fold the cable too far. A common issue I’ve found is people crease the cable with sharp crease when the cable needs to bend around a corner which fatigues the wires. Instead I use a old BIC pen ink straw as a forming brake to roll the cable into a nice smooth arc as the radius of the straw is as tight a curve you want in the cable.
