HDD/SSD speed comparison: why it is now pointless to compare speeds on mechanical HDDs

[glassdarkly]

Mechanical hard drives:
*IOPS = In/Out Per Second
*Random Read/Write - speed at which HDD handles small 4K packets, important for application loading/booting OS, etc

Velociraptor 10000 RPM
Sequential Read: 103MB/s avg
Sequential Write: 103MB/s avg
Random Read: 0.68-0.88MB/s (4k packet size)
Random Write: 0.78-1.7MB/s (4k packet size)
Read IOPS: 170-220
Write IOPS: 195-425
Read access: 7.09 milliseconds
Write access: 3.54 milliseconds

2TB Caviar Black 7200RPM (this is the newest version with 4 500GB platters, the older Caviar Black is substantially slower, even managing to lose to the so-called "Green" drives in certain areas)
Seq Read: 108MB/s avg
Seq Write: 108MB/s avg
Rdm Read: 0.50-0.66MB/s
Rdm Write: 0.42-0.95MB/s
Read IOPS: 125-165
Write IOPS: 105-237
Read access: 11.90 milliseconds
Write access: 6.2 milliseconds

Regular Consumer Drives 7200RPM (Samsung F1 1TB, Hitachi 7K1000.B, Seagate 7200.X, etc)
Seq Read: 91-101 MB/s avg
Seq Write: 90-101 MB/s avg
Rdm Read: 0.40-0.54MB/s
Rdm Write: 0.40-1.01MB/s
Read IOPS: 100-135
Write IOPS: 100-253
Read access: 12-14 milliseconds
Write access: 6.5-7.5 milliseconds
*Exception: Seagate 7200.11/12 have particularly bad access times which are closer to the performance of the green drives, and sometimes worse

Green Drives 5400RPM+
Seq Read: 76-86 MB/s avg
Seq Write: 74-87 MB/s avg
Rdm Read: GG don't care can't be bothered to check
Rdm Write: GG don't care can't be bothered to check
Read IOPS: GG don't care can't be bothered to check
Write IOPS: GG don't care can't be bothered to check
Read access: 16-18 milliseconds for Seagate LP/WD Green/Samsung F2EG
Write access: 8.1-11.6 for Seagate LP/WD Green/Samsung F2EG
*Exception: Seagate LP 500GB has particularly low access times (matching the 2TB Caviar Black's) because it only has 1 platter, for the purposes of this comparison I am mostly looking at mechanical drives with 3-4 platters.

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Solid State Drives:
I haven't included SATA SSDs other than the Intel because the it is very reasonably priced and manages to outperform the competition by at least 2-4x in IOPS/Random read+write. The Intel may lose out a little in sequential speed, but for an 80GB SSD looking at sequential speed is completely pointless unless you are one of those strange people who is getting an SSD for the purpose of copying terabytes of porn back and forth.

That said, most of the Indilinx SSDs are decent options if you are willing to sacrifice at least half the random read/write speed for a discount.

e.g. G.Skill Falcon 128GB, Indilinx controller, about S$495
Random Read: 29.45MB/s
Random Write: 17.07MB/s
(Intel is 2x faster @ only 1.3x the $/GB)


Intel X25-M G2 (last local batch was about S$400 for 80gb, can be ordered cheaper online - Intel has international warranty)
Seq Read: 250MB/s
Seq Write: 70MB/s
Rdm Read: 58MB/s (contrast with 0.68-0.88MB/s for 10k RPM Velociraptor HDD)
Rdm Write: 34.5MB/s (contrast with 0.78-1.75MB/s for 10k RPM Velociraptor HDD)
Read IOPS 35,000
Write IOPS 8600
Read access: 0.09 milliseconds
Write Access: 0.12 milliseconds

Fusion-IO PCI-express SSD (flash memory mounted on a PCI-e card, retails at S$1235 in the US for 80GB; latest partnership with Samsung should ensure that price continues to go down)
Seq Read: 1500MB/s (32k packet size)
Seq Write: 1400MB/s (32k packet size)
Rdm Read: ~720MB/s (4k packet size)
Rdm Write: ~650MB/s (4k packet size)
Read IOPS: 186,000
Write IOPS: 167,000
Read access: 0.05-0.06 milliseconds
Write Access: 0.01-0.02 milliseconds

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As you can see, the differences between the various mechanical harddrives are now so miniscule in comparison to the gains offered by SSDs that there is no longer any point in attempting to distinguish between them. Why pay $50 more for 100 IOPS extra when there are affordable SSDs with 35000 IOPS? If you compare the Velociraptor (~S$180 for 150GB) to the Intel G2 (~$400 for 80GB), the Intel comes up to about 4x the price per gigabyte, but it is also 60x faster when it comes to random reads. After the GPU, the SSD now provides the most worthwhile/visible performance boost for average use.

If SSD lifespan is a concern, consider that Intel has stated that their MLC drives will last 5 years even if you write 100GB/day, which means that it is more likely for the NAND flash cells to lose their charge (this is supposed to happen after ~10 years) than it is for you to exhaust the write cycles on your SSD. From this perspective, an SSD is likely to outlast any mechanical HDDs that you can buy.

[Dr.Vijay]

Good thought

[watzup_ken]

Good write up pal. But one thing to consider is the cost. Not everyone can afford to shell out 400 bucks for an 80GB hard disk. Mechanical hard disks are slow, but clearly, its beauty is its price to space ratio.

[lstdennis]

Where to get Intel X25-M G2? I called Chamoxa but no stock liao. Thinking of getting the 80gig for OS and applications.

[glassdarkly]

Originally Posted by watzup_ken

Good write up pal. But one thing to consider is the cost. Not everyone can afford to shell out 400 bucks for an 80GB hard disk. Mechanical hard disks are slow, but clearly, its beauty is its price to space ratio.

Yep, I am not disputing that (I am using about 5 1TB drives for space and will be getting more soon), but my point is that for OS/speed, SSD is the only option that makes sense. There is no point comparing different mechanical HDDs speed-wise because any gains that could be had between the different models are tiny. For storage all that matters is $/GB (and no reports of drives failing left and right).

Originally Posted by lstdennis

Where to get Intel X25-M G2? I called Chamoxa but no stock liao. Thinking of getting the 80gig for OS and applications.

Even in the US the major retailers all seem to be out of stock.

Right now you can:
1. Bid on eBay (I saw a recent auction close at about 260 USD) + ship with comgateway/vpost/etc
2. Pre-order on Amazon (product page lists 1-2 month wait time @ 244.10 USD) + ship with comgateway/vpost/etc
3. Buy from Malaysia (there's a seller on lowyat.net charging RM 885 who will have stock on 26 Oct, but with 2 year warranty instead of 3 years)

[noinimod]

glassdarkly: Really awesome post. Must have taken a lot of effort on your part, HWZ really needs more posts like these.

I personally cannot wait to get my hands on an SSD, just waiting for prices to drop a lil more.

watzup_ken: You don't get SSDs for mass storage purposes; they're used when speed matters most - O/S, games etc.

[lstdennis]

Agree with TS. Mechanical hdd should be focusing on increasing hd space, in order to achieve as low $/Gb as possible. Main purpose is for storage and a little bit of speed increase for storage hdd is not that important for me comparing to $/Gb. Use SSD for OS and applications to allow system to feel more responsive. Probably for that same $$ of getting a SSD, it will be the most significant improvement you may get/feel from the system.