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Need help to understand what HDD to expect

Posted: Sat Sep 08, 2012 2:05 am
by BeachNut
GA-H55M-USB3
1xWD6401AALS
1xWD10EADS

Ran HD Tune and it's showing average transfer rates of 59.6MB/s and 66.7MB/s. Since these are connected to SATA 3Gb/s ports on the mobo shouldn't I be seeing faster transfer rates than these (eg. at least to the 300MB/s spec for these drives ?)

Could you help with some idea's on how to trouble-shoot this - I have latest BIOS. Are there any specific BIOS settings I should check ?

Thanks.

Re: Need help to understand what HDD to expect

Posted: Sat Sep 08, 2012 2:27 am
by just brew it!
If you're measuring average (sustained) transfer speed, then no you will not see anything close to the peak speed of the interface. Those are both older (few years) drives, and one is a "Green" drive (optimized for low power, not performance).

That said, those numbers do look just a little low; I would've expected something more in the 80-90 MB/sec range for those drives. But even on a newer mechanical drive you're not going to get anywhere near 300 MB/s sustained; you're only going to get that on short bursts that go to/from the drive's internal cache without touching the physical media.

Make sure you've got the latest drivers installed for your SATA controller. But even best case you're not going to see any massive improvements here unless you upgrade to a newer/faster drive (or SSD).

Re: Need help to understand what HDD to expect

Posted: Sat Sep 08, 2012 2:49 am
by BeachNut
Thanks for the quick reply.

I'm also using HD Tune to test a WD My Book Essentials connected via USB3. The max speed is coming in at 131 MB/s. Does this seem right ?

Thanks.

Re: Need help to understand what HDD to expect

Posted: Sat Sep 08, 2012 5:26 am
by Chrispy_
130MB/s could be about right for a WD MBE because if it's a high capacity model it will have extrememly high areal density - the single most important factor for sequential transfer rates.

To date, no single mechanical drive has ever come close to saturating a SATA 300MB/s interface. Here's a copypasta with some very approximate figures for the sequential read speeds you should expect from various devices:

50MB/s - Old IDE hard drive
50MB/s - 5400rpm notebook SATAdrive
60MB/s - 5400rpm "green" edition desktop SATA drive
75MB/s - 7200rpm notebook SATA drive
90MB/s - <1TB 7200rpm desktop SATA drive (lower areal density in older drives and lower capactiy models)
120MB/s - 3TB 7200rpm desktop SATA drive (highest areal density currently available)
140MB/s - 10K enterprise SAS drive or WD Velociraptor
175MB/s - 15K enterprise SAS drive

220MB/s - Five year old, early SSD drive
500MB/s - Current generation SSD

35MB/s - USB2.0 interface (saturated)
350MB/s - USB3.0 interface (saturated)
280MB/s - SATAII Interface (saturated)

As JBI says, your WD Black drive should be faster than you're seeing it, so check you have the correct drivers installed for your motherboard chipset and try a few other tools. HDTach or Crystaldiskmark will give you second and third opinions, since different tests measure the drives in different ways.

Re: Need help to understand what HDD to expect

Posted: Mon Sep 10, 2012 4:32 pm
by DPete27
What OS are you using? (possible misalignment?)

Re: Need help to understand what HDD to expect

Posted: Wed Sep 12, 2012 7:52 am
by BeachNut
W7 x64

BIOS also updated to latest version.

Test on another PC with same Black Caviar drive and OS with similar speed results.

Can you expand on the misaligned suggestion ?

Thanks.

BTW. HD Tune screwed up my W7 boot on the second PC. Good job I had a recent image to recover to. No more HD Tune !

Re: Need help to understand what HDD to expect

Posted: Wed Sep 12, 2012 8:13 am
by just brew it!
BeachNut wrote:
W7 x64

BIOS also updated to latest version.

Test on another PC with same Black Caviar drive and OS with similar speed results.

As I noted before, this is an older drive. Even though it is a Caviar Black, the numbers aren't going to be anything to write home about compared to current drives. While your numbers do look a LITTLE low, they're not ridiculously low. Even if you got the maximum performance this drive is theoretically capable of, you would probably notice little or no difference in actual usage.

BeachNut wrote:
Can you expand on the misaligned suggestion ?

On many newer drives the native sector size is 4K instead of 512 bytes; this is referred to as "Advanced Format". If you have an Advanced Format drive and your partitions aren't aligned on 4K boundaries you can take a substantial performance hit, especially on writes.

I'm pretty sure this is NOT your problem, because A) the drive is old enough that it is almost certainly NOT an Advanced Format drive; and B) Windows 7 should take care of the 4K sector alignment automatically.

BeachNut wrote:
BTW. HD Tune screwed up my W7 boot on the second PC. Good job I had a recent image to recover to. No more HD Tune !

If you use HD Tune Pro (paid version) and enable write tests, it writes to the raw drive (ignoring your partitions and file system). This is necessary to get accurate results. A warning pops up to let you know that it will destroy data.

If you WEREN'T using HD Tune Pro (i.e. you were using the free version), then HD Tune wasn't the reason your drive got screwed up.

Re: Need help to understand what HDD to expect

Posted: Wed Sep 12, 2012 10:09 am
by frumper15
I just ran HD Tune on my 640 black and got 77.6 MB/sec average so you're maybe 10 MB/sec lower. It's possible you have a driver issue or something else going on there, but it's not a terrible rate by any means. I've pretty much resigned myself to the fact that I'm going to need to use SSDs for the boot drive on all my computers now that I've been spoiled by one. Not that sequential rate is huge issue for the OS, but the random reads/writes are orders or magnitude faster than a mechanical.