Olyphant Upgrade: Seagate 2TB SSHD

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I recently upgraded the internal drive of our 27″ mid-2010 iMac from the original 1TB Seagate to a 2TB Seagate SSHD. At under $150, it’s the perfect balance of speed, price, and capacity. I highly recommend the drive. Read on for details….

The 2010 iMac internal drive is often tricky to upgrade. Not only is the job itself more involved than your standard PC replacement, but drives on this vintage of iMac have a hard drive heat sensor. If the internal drive you replace it with doesn’t have a similar sensor, you either need to add this in with a third party adapter, or install software to ignore the sensor. Otherwise you get loud fans spinning constantly.  Much to my surprise, the Seagate ST2000DX001 has the same pinouts for the temperature sensor as the original drive., so no additional hacks are required. Lucky me.

Other advantages of the replacement drive are that, while doubling the capacity and significantly improving I/O performance, the replacement drive is much quieter than the original.  The iMac still isn’t silent, but it’s much closer than it was before.  The was another unexpected and pleasant surprise.


However, capacity aside, the biggest improvement is undoubtedly the performance improvement.  Here are some numbers taken quickly with Blackmagic Disk Speed Test available through the Mac App Store:

   Drive               Read   Write (MB/S)
1) Seagate SSHD        175    175
2) Stock Drive         110    115
3) FW800 Stock         65     80
4) Lacie SSHD USB      25     20
5) Lacie SSHD FW800    66     65

1) Is the ST2000DX001
2) is the original Seagate 1TB drive
3) is a Lacie external enclosure with a 2TB Hitachi 7200 RPM disk connected via Firewire 800 (This Mac predates Thunderbolt and USB 3.0)
4) is the Lacie enclosure connected via USB 2.0 with the Seagate SSHD
5) is the Lacie enclosure connected via FW800 with the Seagate SSHD

My conclusions:

  • The SSHD has an 8GB SSD buffer ahead of the 2TB 5400 RPM disk. Performance improvements depend on usage patterns. The drive adapts as it detects where you will be reading and writing on the disk. Running the benchmarks repeatedly, you can watch this adaptation. Initial runs were occasionally slightly worse than the stock drive but they quickly improved on repeat runs.
  • If your usage patterns are random, you may not see a brilliant improvement over a traditional disk, particularly if you’re already using a 7200 RPM drive. However:
  • After a few days of use, anecdotally, the machine feels much faster overall. Launching programs isn’t as blindingly fast as it would be with a pure SSD but it absolutely feels twice as fast for normal, repeat operations.
  • The Seagate SSHD drive makes perfect sense as a large-capacity replacement for a machine that can on;y handle one 3.5″ SATA drive. If you can install two drives and cost isn’t an issue, an SSD for the OS and a large spinning disk or SSHD for data will be faster, but in a machine like the iMac, this is certainly the best option for me.
  • Buying this drive and putting it in a USB 2.0 or Firewire enclosure looks to be a total waste. Save your money and buy a standard 5400 RPM drive if this is your plan. (It would have been nice to also run this test with USB 3.0 or Thunderbolt. If I get the chance in the future, I’ll test this as well.)

Overall, this looks to have been the right drive for my uses. I recommend it.

GoSaBe Blog - Jan 25, 2015 | Hardware, macOS