Can I Raid 0 15" Early 2011 i7 2.0 GHz running High Sierra?

Sadly, you just can’t setup a RAID set in this laptop using SATA III (6.0 Gb/s) drives. This series has a defect in the optical drives SATA port which won’t link up with your drive correctly. You could setup a RAID set using slower fixed SATA II (3.0 Gb/s) speed drives (HD’s) but why would you do that? When a single SSD drive can saturate the SATA III (6.0 Gb/s) bandwidth unlike HDD’s.

In a RAID set the I/O needs to be the same Both SATA and type of drive (matched).

So what is SATA data rates and why is that important here?

The SATA interface like many has been improved upon over time. Just look at Ethernet when it was first setup on UTP wiring it was only 2.94 (3.0) Mbps!, then came 5 Mbps, 10, 100, 1000 and then we jumped to the gigabit speeds of 1 Gbps and then onto 10 Gbps! But that was the limit of copper wiring we are now into fiber optics moving forward.

But, just sticking with the copper world of Ethernet in the early days you needed to replace all of the devices when you introduced a newer system which was using a faster interface so as an example when we had a 10 Mbps flat network and you dropped in a 100 Mbps system the 100 system would not have any way of communicating with the other systems. Which is why layer 2 switches came out which allowed mixing speeds as the switch would buffer the data when the data needed to be transmitted on the slower network. We also so the introduction of sensing logic within the adapters so they would sense what the network was running at and match it.

The SATA interface likewise jumped from the original 1.5 Gb/s SATA I spec to SATA II running at 3.0 Gb/s and today we are at SATA III which runs at 6.0 Gb/s. Like Ethernet one needed to use the same speed I/O drive as the system was as it would not work correctly at the very beginning. In the early days SATA drives had jumpers to allow you to alter the drives I/O speed (mostly during the SATA I to SATA II days). When the drive makers moved to SATA III the jumper was still offered but it would push the drive down to SATA I I/O speed. Over a bit of time the tech Ethernet was using to sense the network speed was brought over the SATA as the drive makers when getting lots of returns of drives which where not bad physically but the data was often messed up as people would force the SATA II or III drive in SATA I or SATA II systems respectfully and as the data flow was not excessive they appeared to work and then die in a few weeks! So we use the terms Fixed speed and Auto speed to describe which type of drive it is. Sadly, there is no standard term that the drive makers use as the SATA standards group could not come to terms with this issue. Mostly you need to review the drives spec sheet to see what it states as an example:

• 3.5” Seagate FireCuda SSHD
• 2.5” Samsung 860 EVO SSD

Note how both drives list all three SATA I/O speeds. But now lets look at this drive:

• 2.5” Seagate FireCuda SSHD

Note how only one SATA I/O speed is listed

Now you would think the 2.5” version of the FireCuda would be the same as the 3.5” but its not! Seagate pulled the auto sense circuitry out! As the demand for SATA I or SATA II drives has dropped off as these older systems are not being upgraded as much as they once where. The use of the circuit costs money! So to be price competitive with 2.5” SSD’s Seagate made the call to pull it. Most of the 2.5” drives are now fixed speed again! SATA III (6.0 Gb/s) only.

Also, Apple’s HD SATA cable in the original system was only rated for SATA II I/O speed. So you will also need to replace the cable to the newer one that supports the higher SATA III I/O speed MacBook Pro 15" Unibody (Mid 2012) Hard Drive Cable This is the better version of the cable! But there’s a bit more, you’ll want to protect it by placing a strip of electricians tape on the uppercase where it crosses as the rough aluminum surface can damage it. You also don’t want to fold the cable! The creasing of it will damage it! Instead you was to form a arc using a BIC pen Ink tube (empty) to help you form the radius were the bends are needed. And lastly you want to make sure the black plastic clips in the uppercase are not damaged. I always make sure the on near the optical drive is OK if not you’ll want to build a bit of a cushion on the two edges of the optical drive where the cable crosses over top at both ends so if the bottom case bends it won’t damage the cable.