Performance vs. Capacity

I typically turn to HDTach for my performance vs. capacity graphs. Normally they are used to show SSD performance degradation without TRIM but in this case I genuinely wanted to see what the performance falloff was as you filled the drive up. HDTach had issues with the > 2TB of addresses on this drive so I used HD Tune instead.

Hard drives store data in circular patterns. Reading/writing to the outermost LBAs is faster (that’s just how circles work, you can cover more area in a single rotation on the outer track vs. the inner track). As a result, HDDs write data at the outmost part of the platters first and as the drive fills performance drops.

Sequential Read Performance vs. LBA

Sequential Write Performance vs. LBA

Peak performance, we’ve already discussed is at around 150MB/s over USB 3.0. Sequential performance at the highest LBAs drops to around 75MB/s. There’s one anomaly that I saw in my tests which you can see in the graph above. Performance drops down to 16.2MB/s for sequential writes in the last 100GB of the drive. This could be a problem with my particular drive or an issue related to the early nature of these 3TB drives.

USB 2.0, 3.0 and FireWire 800 Performance The Heat Problem
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  • Belard - Monday, August 23, 2010 - link

    ALL brands have their bad batches. Maxtor, WD, Hitachi-IBM, etc... and even intel.

    I have used lots of Seagates and Maxtors with good reliability. Yes, I've had failures - but not really any more than WD.

    In the OLD days, Seagates were called "Sea-crates" typically used in cheap PCs ($2000+ computers) - I'd never touch those junky RLL drives. I bought Quantum SCSI drives which were higher end, more reliable and costs more money... and being SCSI - they were much faster. I miss Quantum. :( Today, I buy Seagates - they are easily quieter than most drives - with only Samsung just as quiet.

    I still buy 1TB Seagates. I don't trust the 1.5~2TB drives from anyone. But the tech used in 2~3TB drives are filtered down to the 500GB drives (single 500GB platter) - so the density reliability issue is there - but the less-parts (heads and arms) factor does help. So todays 500GB drives are very thin... wow! ;)
  • mewgirl - Monday, January 31, 2011 - link

    ....But since WD is THE WORST manufacturer of external hard drives, this post means you are definitely NOT recommending Seagate, then, correct?
  • mino - Monday, August 23, 2010 - link

    You should NEVER use an on-demand cooling system with magnetic storage.

    Hard disks are an order of magnitude more sensitive to temperature changes than pure high temperatures.
  • Jonathan Dum - Monday, August 23, 2010 - link

    Interesting. Proof to back up that claim?
  • has407 - Monday, August 23, 2010 - link

    The OP is nominally correct. While I wouldn't go so far as to say "NEVER use an on-demand cooling system", I'd say they're likely to do more harm than good unless carefully engineered and integrated with the HDD.

    Rapid changes in temperature can kill a drive faster than elevated temps due to, e.g., thermal expansion/contraction of components (heads, platters, spindles, etc.), and air density changes which affect head ride height.

    Those changes require active adjustment and compensation, and are necessary and common in today's drives/controllers. However, there are limits. Drive manufacturers specify a maximum temp change/time (even if it may not show in the data sheets available on their web site).

    The best solution is to maintain a steady and moderate temperature change. The worst solution is a typical/cheap "bang-bang" controller that starts/stops when temperature limts are reached, and which causes rapid changes in the drive's temperature.

    Case in point: The absolute worst thing you can do for your laptop drive after leaving it in the car for hours on a frigid day is drag it into a warm room and immediately start pounding on it. Virtually guaranteed to result in errors and reduced life (if not short-term failure).*

    In short, active cooling is not necessarily bad, but stupid active cooling that causes wide temp swings over short periods in the drive can cause far worse problems than allowing the drive to run at an elevated and slowly changing temp.

    This has been a problem for many years, and increasingly as tolerances decrease (especially with higher track densities). While drives/controllers continue to adapt and improve, it's still a significant factor, and the larger the media the worse the problem. For recent papers (sorry, don't have any recent freely available links), see:

    * Yes, people talk about the "freeze your HDD" to try and recover it. (It may even work--never tried it.) But subjecting an HDD to that kind of rapid temperature change abuse even occassionally is guaranteed to kill it in short order.
  • JonnyDough - Monday, August 23, 2010 - link

    It makes a lot of sense, even without the links. The hardest thing on a car is starting it in the dead of winter when there's no oil up in the engine. It grinds, and then as the friction causes it heat up quickly with cold oil it continues grinding until it is warm and coated in oil internally.
  • mindless1 - Monday, August 23, 2010 - link

    That is wrong. If you have a constant speed/always-on cooling system, it means that the drive changes in temperature as it wakes up, reads and writes, and more as it keeps running.

    If you have on-demand, as the drive starts to warm the fan kicks in and keeps the drive at a more constant temperature, including increasing fan RPM as needed to keep the drive at the same temperature! Plus, with on-demand all those times you are not using the drive and it is sleeping and at low temperature, your fan isn't pulling in dust to clog up things.

    Also, it IS high temperature that does damage. Granted, yes it has to change temperature to get to a high temp, but the more the temperature changes the more the different coefficients of expansion come into play. For example, you can stretch a rubber band all day long, but if you stretch it too far it starts to rip apart.
  • Belard - Monday, August 23, 2010 - link

    This or anyone else... should have minded the heat problems. There are external cases for HDs that have an 80mm cooling fan - low RPM.

    My Seagate drives in my case (1TB) are currently 39c... I run my fan at LOW speed to keep the noise to pretty much silent. A drive hitting 50c+ would make me nervous... 60+ is VERY bad!

    And for a 3TB drive holding that much data, RELIABILITY is most important! USB 3.0 and such are important features when moving that much data and it'll slow down when you're using the drive for what it is intended?!


    The dock is a handy, but a wider one would be nicer... there are other dock-drive designs out there, some with dual docks. Generic versions that allows you to put in ANY drive would be the way to go. OR better yet... use the HOT-SWAP abilities of eSATA and pop your drive into a drive bay on your computer - NO DOCK NEEDED!

    Theres about 60+ options on Newegg. Many docks, you just plug in your drive - sans case.
  • Aikouka - Monday, August 23, 2010 - link

    Heat problems are one of the reasons why I'm starting to shy away from Seagate drives after using them for a few years. A few months ago, I noticed that one of my WD 1TB HDDs was exhibiting some odd file read issues. When I opened up my server, I found it right above a Seagate 1TB HDD, and when I tried to pull the Seagate drive out, it was almost too hot to touch!

    Of course a (mechanical) hard drive will produce heat, but the Seagate seemed to be in a league of its own compared to all the other drives in my file server. I'm really not sure what brand to even go with now... I purchased a Samsung drive based on recommendations, and that drive died after only two months (the whole random disappearing act leading to refusing to ever show up). I recently purchased a WD 2TB drive that came up clean in a full-disk error check, so we'll see how that goes!
  • mindless1 - Monday, August 23, 2010 - link

    Your server is not set up correctly, blame it not the drive. A proper case configuration for stacked drives leaves at least 1cm or so between each and ample cool intake airflow through the drive rack. In that scenario you will have no problem cooling any 7200 RPM drive, or with higher airflow rate, 10K RPM drives too.

    Also, there is not a significant difference in operating power or running temp of equivalent drives from Seagate vs other brands. Single-digit # of degrees is not enough to matter one way or the other till you reach the upper limits.

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