Just noticed what I believe to be very slow HDD speeds; SATA questions...

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tAKticool

tAKticool

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Apr 10, 2013
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Hi everyone-

My long story short is that, last August, with tons of help from this forum and it's righteous peoples, I bought and built a fairly high-performance PC that has generally been flawless. I have a small HyperX SSD for Windows 10/boot etc. and some apps (generally only things that automatically install themselves in the C: drive, otherwise I'd use the HDD) , and a WD 1TB HDD for storage and programs etc. I try to use the WD for everything I don't NEED the SSD for, as it's only a 120GB, you only get ~111GB to use, and after the clean install of Win10 and some other odds and ends, I have 85.5GB - plenty to some but it goes fast etc.

ANYWAY, I have a WD BLUE 1TB HDD, SATA 6 Gb/s 7200RPM drive, connected to my ASrock Z97 OC Formula MoBo which also has SATA 6 Gb/s connectivity. I even bought some (what I believe to be high-quality) Coboc SATA III 6Gb/s cables to connect stuff. I have never even THOUGHT about whether I did everything correctly or if I had a problem until just now -- I had a problem with a cellphone going into the drink, and I decided to copy my microSD music card to my computer. I put it on my HDD yesterday, then decided to copy the whole whatever it is, say 6GB collection, to another folder on the HDD. It took a minute or two to complete, and was about 50-58 MB/s transfer speeds at first, going down to about 40-49 MB/s for the majority of the copy procedure. By my "calculations", 6Gb/s = 750 MB/s , so I wasn't even getting 10% of the possible transfer speeds?


Am I looking at these figures wrong or am I doing something wrong? On the one hand, I guess it's no big deal, but if I'm supposed to be getting 10x faster speeds on my harddrive, I must be doing something or have done something wrong, right?


Thanks very much!
 
Solution
nukemaster
Within the same drive is actually a bit slower because the read heads have to move from location to location(added latency). If you want to move something on the same drive, use Cut instead of Copy. This will be nearly instant in many cases.

The 6 gigabit is the rate that the controller on the board can talk(and clearly the wires have to be good for this speed, but most are. The drive controller has to be capable as well, but it never means the underlying media will be able to max it out) You have some overhead that prevents ever seeing that MAX sata speed even with an SSD.

Changing bios settings after the OS is installed can cause issues sometimes. Setting the SATA ports to AHCI before installing windows would have been recommended...
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nukemaster

nukemaster

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Nov 23, 2004
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Hard drives are nowhere near fast enough to saturate the SATA III connector.

In fact with lots of small files a hard drive can get down into the sub 10 megabyte.sec area. With large non fragmented files speeds of 150-200 may be possible with some drives(this is near the start of the drive only since the speed drops with time.).

This is a raw sequential chart from a slower(low rpm) hard drive.
All drives loose speed as you get towards the end since the inside of the platters are turning slower.
mlnklu.jpg

As you can see under some workloads, hard drives get slow.
33xjvv4.jpg


1 gigabit is 125 megabytes(1000/8=125).

You may also be at the mercy of your card reader or other devices.
 
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tAKticool

tAKticool

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Apr 10, 2013
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nukemaster,

Fair enough thank you very much for your reply and information.

Just to make sure I was clear- the card reader didn't come into it. I copied the folder from the card (via card-reader, true) YESTERDAY, into one area of my D: drive, then today I realized I wanted it in another area - and I made a conscious decision to copy the folder from lets say something like D:\Junk\Phone Memory Card Dump Folder\Music to D:\Music when I made the transfer today. It occured to me to see how it would work transferring/copying files HDD to HDD. It sounds like I got a decent rate all things considered, after I posted I did a lot of Googling, many people state that the 6Gb/s and other advertised rates are how fast THE WIRES are capable of transmitting the data, not actual rates they get transferred at and certainly not real-word end-user speeds.

This is not my area of expertise though so I wanted to consult with the brain-trust, I was worried you or others might say "Oh you didn't connect your stuff right" or "you need to mess with BIOS" etc.

Thanks again ser
 
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nukemaster

nukemaster

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Nov 23, 2004
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Within the same drive is actually a bit slower because the read heads have to move from location to location(added latency). If you want to move something on the same drive, use Cut instead of Copy. This will be nearly instant in many cases.

The 6 gigabit is the rate that the controller on the board can talk(and clearly the wires have to be good for this speed, but most are. The drive controller has to be capable as well, but it never means the underlying media will be able to max it out) You have some overhead that prevents ever seeing that MAX sata speed even with an SSD.

Changing bios settings after the OS is installed can cause issues sometimes. Setting the SATA ports to AHCI before installing windows would have been recommended and with some tweaks can be set if required.

You need very small files to get to those low points under 10 megabyte/sec and worse.

The primary thing you should worry about with any drive is keeping an eye on SMART status and having a backup since any drive can fail.
 
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Solution
tAKticool

tAKticool

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Apr 10, 2013
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Thank you very, very much nukemaster, you went above and beyond the call twice, reminded me how awesome this forum can be and how knowledgeable and outstandingly full of help people here are!
 
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