Data transfer speeds: what's "normal;" how to improve

Rhythmdvl

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Nov 14, 2007
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I am transferring 6.5 GB of files between two drives. Windows' basic copy operation (i.e., just copy/paste from Explorer) is reporting a speed of about 9.75 MB/second. This feels a bit slower than expected — even accounting for overhead and differences between theoretical and actual maximum. But then again, what do I know? Not that much, but enough to ask questions. Is this speed about right? If not, where would I start troubleshooting/tweaking?

Thanks,

Rhythm

The environment:
It's a fresh Windows 7 64-bit install, both drives were factory fresh. At the moment there are no anti-virus or other firewall-like programs installed. The source drive is a Crucial 128 GB SSD; the destination drive is a Western Digital Black 7200 RPM 500 GB drive. These were the first files copied to the destination drive. Both are connected to the motherboard's (Asus P6T) SATA controller. If it makes a difference, there are also 6 GB of G.Skill RAM in there, and the CPU is an i7 920.


 

phantazm

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Dec 17, 2009
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Rhythm,

I am experiencing a similar issue on my vista 64 system reading from raid1.

I have posted a request for help in this forum.
So far as a temporary solution the only thing that seems to help me was to turn off volume write back cache.

In your case you may with to go to manage system and check policy settings for each drive. Careful with advance performance settings as you may sustain data loss in case of a power outage if you are not running a UPS.

I hope this helps.

Regards,
Phant

PS how is the speed going the other direction?

 

phantazm

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Dec 17, 2009
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Rhythm,

I get up to 100 MBps on my none raid drives

avg 30 - 50



 
Is it a bunch of small files, or a few large files? If it's a bunch of small files, then it's not surprising at all - unless you're using a command line method such as xcopy, there will always be a significant slowdown when copying a ton of small files. If it's a few large files, you should be getting much closer to theoretical though - I routinely see >100MB/s when copying large files between my Velociraptors and Barracuda XT, and I've briefly seen >200MB/s when copying from my X25-M to my velociraptors. Those numbers are all for individual files >1GB though - it runs MUCH slower when copying small files, like a folder full of thousands of pictures.
 

leo2kp

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I agree, a lot of smaller files will kill transfer speeds because of the rotational latency of the mechanical drive. I have a 750GB WD Black drive and two Velociraptors in RAID-0 and I see performance swings from 10-100mb/s depending on file size. Find a large file and paste it to your 500GB drive and see what the transfer rate is. That would be a more accurate test of maximum performance. If you don't have one, try zipping 1 or 2GB of MP3s and move the zip file over.
 
It's not the rotational latency of the drive that is killing the transfer (as long as the files are grouped in one spot) - you can test this because if you use a command line copy such as xcopy, the speed will be MUCH higher. What's killing it is the way windows handles file copies - the more files there are, the more overhead there is.
 

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