Does Hard Drive Orientation Affect Performance?

About a week ago, someone in the Low End Mac Facebook group posted the following question:

Obviously we’re all used to the horizontal drive orientation, and the externals tend to have vertical orientation, but is the vertical really a safe orientation? Obviously there’s the chance of it being tipped/knocked over, but even a mild tilt during writing is bad from what I understand.


It was the first response that grabbed my attention:

I remember reading articles on this in the 90s, generally they said that in vertical position the drives might be slightly slower and also to format them in the position you’re going to use them (!!!). I kinda regarded those as myths, though.

This Is a Thing?

What? This blew my mind, I had no idea that was a thing. I’ve always used my hard drives however it fit my needs and never noticed a change in behavior or performance if the orientation changed – but then again, I didn’t have my first external hard drive until 2007. This is probably relevant, as some searching online yielded the following snippet of information:

At one time (long ago) manufactures advised against changing the orientation of a drive without reformatting it. This was due to the heads being affected by gravity and becoming misaligned with respect to the data. I have not seen such a notice in quite some time.

This came from a 2012 article, and if drive orientation no longer mattered at that time, it certainly won’t today. Granted, that article focuses on hard drive wear, not performance. It’s the performance angle I’m interested in.

Does this still affect hard drives today in one way or another? Unable to find more information on the subject I decided to do some testing of my own so I grabbed a few hard drives and got to work.

The Drives

  1. A bare 3.5″ 20 GB Western Digital IDE from the year 2000, the oldest drive I could find
  2. A bare 3.5″ 80 GB Maxtor IDE 5400rpm from the year 2002
  3. A 3.5″ 1TB Hitachi SATA 3.0 Gb/s 7200rpm from the year 2009, inside a LaCie external
  4. A bare 3.5″ 1TB Seagate SATA 3.0 Gb/s 7200rpm from the year 2011
  5. And finally a bare 3.5″ 4TB Western Digital 7200rpm from the year 2013

I was hoping for a better spread year-wise, but this is all I could find.

The Tests

  1. Each drive will be positioned horizontally, formatted, and an AJA speed test will be done.
  2. Each drive will then be positioned vertically and without re-formatting, AJA speed test will be done again.
  3. Each drive will then be reformatted while positioned vertically, AJA speed test will be done again.
  4. Each drive will then be returned to a horizontal position and without re-formatting, you guessed it, AJA speed test will be done again.
  5. Loop back to test 1 and re-run it in case the results were poor due to the drive being cold.

These tests will be repeated three times with AJA at default settings for each drive, and the average of all results is the final speed. The IDE drives had a test file of 1 GB while the SATA drives used a 4 GB test file. This is done to make the test duration similar across all drives. The IDE drives were used with a powered USB 2.0 IDE adapter, the SATA drives were used in a USB 3.0 enclosure, except for the LaCie, which was used over FW800.

While not a huge sample set, this should give me results reliable enough to put this question and potential myths to bed, so let’s begin!

The Results: IDE Drives

20 GB Western Digital – 2000

Starting with the oldest hard drive I could find, figuring this is the most likely candidate to prove/disprove the theory that formatting and orientation (F&O from here on out) affects performance. Here are the results:

There was no difference in performance when the drive was both formatted and tested horizontally or vertically. When the drive was placed in a different orientation than the formatting, the performance took a hit – as much as 1 MB/sec and as little as 300 KB/sec. Interesting results.

Publisher’s note: There is a maximum difference of 5.2% for writes and reads, the biggest difference found in this testing.

80 GB Maxtor – 2002

Only two years newer, but hard drive capacity and technology was still taking pretty big leaps at that time, so maybe not susceptible to the orientation performance hit? Let’s see:

As with the previous drive, there is no difference in performance when tested in the same orientation it was formatted in. Changing orientation without reformatting cost 1 MB/sec in read performance consistently and 300-700 KB/sec write performance. That’s two out of two. I need to know if this issue affects IDE drives consistently, but my other IDE drives are in use in various PPC Macs.

Publisher’s note: The difference in writes speed is 3.0%, the second-largest difference seen in this testing, while the maximum difference for writes is 2.5%.

Alright, I pulled them, backed them up, and formatted them to run the tests. Three other drives joining this test:

  1. A bare 3.5″ 80 GB Maxtor IDE 5400 rpm from the year 2002 (same as the first Maxtor, both from the same X-Serve G4)
  2. A bare 3.5″ 80 GB Western Digital IDE from the year 2002
  3. A bare 3.5″ 60 GB Western Digital IDE from the year 2003

The second 80 GB Maxtor IDE performed exactly the same as the first, so I won’t bore you with another graph.

80 GB Western Digital – 2002

This is where it got interesting for me. The 2002 Western Digital could not care less what the formatting and orientation were. Each test was identical to the last.

60 GB Western Digital – 2003

This Western Digital, one year newer than the previous drive, actually performed slightly better with the ‘wrong’ F&O combo! I ran all the tests on this drive again and the results were consistent.

In the early 2000’s Western Digital overtook Maxtor in reliability and performance, and this (extremely limited) test shows that perhaps Maxtor was already unable to keep up technology-wise several years before Seagate scooped them up. Western Digital seems to have overcome the F&O hurdle while Maxtor was still affected by it. Of course, I’d need more drives from both brands in these year ranges to confirm this. For now, this is what I had, so I’m rolling with it.

Publisher’s note: Read performance is 0.95% lower in the vertical orientation, something you are unlikely to notice. But if you are looking for the best possible speed, horizontal wins here.

Fast forward five years. IDE drives are a distant memory for most and SATA is all the latest. How do these new drives perform?

The Results: SATA Drives

1 TB Hitachi – 2009

Five years is a lifetime in the hard drive world. So has that hurdle finally been left in the past?

It appears so. This drive performed the same in every test regardless of formatting or orientation.

1 TB Seagate – 2011

As expected, this SATA drive did not seem to be bothered by the F&O hurdle either. What is interesting to note, however, is that this drive performed better in the horizontal orientation, regardless of formatting.

I ran these tests several more times, and the results were consistent. This drive just doesn’t like being vertical as much as it likes being horizontal.

Publisher’s note: The difference in write speeds is just 0.8%, and for writes, just 0.2%, something you are unlikely to notice unless you are running benchmark tests.

4 TB Western Digital Black – 2013

At this point, we can make the safe assumption that a hard drive these days can be used in any orientation and formatted however you want. But as I had the drive available, I figured I’d run the tests. Might as well be sure, right?

What’s this? A 1.7 MB/sec performance hit in write speed when the orientation changed without reformatting? That can’t be right! This drive was built 11 years after Western Digital overcame the hurdle. I grabbed another 4TB WD Black and ran the tests again – exact same results.

Publisher’s note: The overall difference is 1.1% in write speed, something you would never notice.

With no newer hard drives available for testing, I can’t tell you if this is a Western Digital thing, a 4 TB thing, or a 2013 thing. There were some supply issues for hard drive manufacturers in 2011-12 due to the floods in Thailand, but that should not have impacted the parts they put into this late 2013 drive (some vendors would put cheaper parts in their drives when parts were hard to come by). One is left to wonder.

Is Vertical Orientation Really Safe?

Even if F&O does not affect a drive, there is still the question: Is vertical orientation really safe?

That depends entirely on your setup and environment really. If you have a house full of pets or kids and your desk is accessible to all of them, I would not put any hard drives in a vertical orientation. The chance of it getting knocked over is far too great. If you have a solid dock a hard drive stands in, the chances are diminished. Horizontal is my orientation of choice because I do have my son and several cats running around me all the time.

Heat is another consideration. I’ve heard it said that a hard drive in the horizontal orientation runs hotter as more heat accumulates under the drive. Then again, I’ve also heard the opposite: hard drives push heat through the metal cover so it will run cooler when positioned horizontally. A hard drive in vertical orientation accumulates heat at the top of the drive, so it runs hotter, but on the flip side, a hard drive positioned vertically runs cooler because no heat accumulates underneath it.

In the end, only testing with a close eye on temperatures will prove or disprove any of the above. Something that’s not possible for most of the old hard drives still in use as no temperature sensor or S.M.A.R.T. data is available to monitor.

Conclusions and Advice

If anything, this limited testing shows that even more recent drives should be tested to see if they function better when horizontal or vertical. While the formatting might not have an impact on performance, the orientation might. This is, of course, Low End Mac, so I’m sure there are plenty of old hard drives still in use. Sure, some old Macs have been upgraded to CF cards, but others prefer the humming and rattling of the old hard drives.

With any IDE/SCSI hard drive from 2002 (2003 if you want to play it safe) or earlier, F&O definitely have a considerable impact on performance, so it’s important to format those in the orientation they will be used in. I think back to my Power Mac G4 MDD days where I swapped hard drives with other Macs all the time, a drive would go from being horizontal inside a Sawtooth to being vertical in the MDD – and I probably lost precious megabytes per second because of it.

With hard drives becoming greater in capacity and faster, a few megabytes speed loss will be hard to notice. But I’m sure you’ll want to get the most from your hard drive, so it can’t hurt to test and make sure the most is exactly what you’re getting.

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