SSDs in older Macs are slower, but still pretty freaking fast

blogEntryTopperSATA II, SATA III, 6GB/s, 3GB/s -- here's what you need to know if you're putting a new SSD into your older Mac. WhatSATA you say? Click-a through to find out. I'll make it fast.

What is SATA?

SATA stands for Serial Advanced Technology Attachment. It is the interface between your hard disk and computer. More semi-specifically, the SATA connection plugs your hard drive's controller directly into the motherboard -- brain to brain, as it were -- enabling super high-speed data transfer. This is your drive's SATA bus:

sata-drive-300

Meet the SATAs

Now let's talk about data transfer rates. SATA speeds are given in Gb/s -- gigabytes per second. There have been three revisions to the SATA standard so far, here are their rated speeds:

  • SATA 1: 1.5 Gb/s
  • SATA 2: 3.0 Gb/s
  • SATA 3: 6.0 GB/s
It's important to point out that these speeds are theoretical -- technically, the interface can reach those speeds, but actual data transfer will not. I could theoretically break the sound barrier if someone had a million-dollar check with my name on it and was running away from me, but in reality I would be panting after 30 feet and would have to stop and throw rocks.

A good rule of thumb is to divide the SATA speed by 10. So with a SATA 2 interface at 3.0 Gb/s, you'd get up to 300 MB/s throughput. Real-world will be even less than that.

Drive SATA and computer SATA are independent -- you might have a SATA 3 drive but a SATA 2 Macbook. Fortunately, SATA is fully backward-compatible. You can put a SATA 3 drive in a SATA 2 Macbook, and it will work perfectly, just at the lower speed. Which brings us to...

What's your SATA?

In general: if your Macbook is a 2010 or older, it has SATA 2. If your Macbook is early 2011 or newer, it is SATA 3.

If you are buying an SSD today, it's going to be a SATA 3. So if you are putting it into a pre-2011 Macbook, understand that you'll be getting SATA 2 speed. That may sound like a bummer -- you're getting only half of what you're paying for -- but an SSD is SO much faster than a mechanical hard drive, that you will still be blown away by the difference.

My results

I have a late-2008 Macbook Pro. I've installed a Crucial M500, 960GB. My benchmarks, using Blackmagicdesign's Disk Speed Test:

speedtest-400

Pretty decent, especially for a 6-year-old Macbook. Compared to my previous drive, this SSD upgrade has given me about a 250% increase in speed. Using it every day, it feels even faster than that.

Final thoughts

If you have an older Mac, an SSD is possibly the best investment you can make short of buying a new computer. Everything feels snappier. Apps load in one bounce. Opening and saving are super fast. And it's much quieter.

If you're thinking of upgrading your Macbook to an SSD, I have two words:

do it.

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