What is a normal speed for copying large files within the same hard-drive on a modern desktop PC (7,200RPM SATA single-drive, Quad-Core CPU, plenty of memory)?

And how fast can you go if you really optimize it for no purpose other than to boast a very high file-copying speed?

Please quote some real numbers, not stuff like "oh if you do RAID-0 it should get really fast" :)


Also, I'm getting copying speeds which are only 1/4th those reported in the answer below, where should I look to try and optimize it?

  • I finally found the reason, and it was pretty stupid. My data drive had somehow become configured with NTFS compression. The blue colored font on the folders totally escaped notice until one day I had a "flashback" and remembered what it meant :) – Alex R Dec 22 '09 at 0:48

This has very little to do with CPU / memory and more to do with the hard drives and their connected controller.

Just did a little unscientific test -

Transferring a 358Mb file from one partition to another on the same machine took 9 seconds.

Transferring a 238Mb file from one disk to another disk took 3 seconds.

Both drives are 7200RPM SATA 2 disks with 16MB cache.

  • And of course transfering lots of small files will be much slower. – Shane Kearney Nov 14 '09 at 19:41
  • Very interesting. I'm getting only 10 MB/s copying a large file (20GB) within the same SATA drive. That is only a fraction of your throughput (near 4x factor!). I had suspected mine was way too slow, that is why I posted this question. – Alex R Nov 14 '09 at 21:15
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    And of course transferring a file larger than the Windows memory cache size will be much slower. – harrymc Nov 14 '09 at 21:34
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    If you are getting very slow speeds, defragging your hard drive may help. 10MB/s does seem rather slow for SATA - I would check Anti virus settings or any sort of other file level checker. The largest file I could find was a 4GB iso from Technet... Copying it on the same drive was about 42MB/s, then after a few seconds it went down to 39, and then went at around 30MB/s for the remaining... so, the larger the file,the slower it gets over time... If you want me to test any specific scenario, please say and I will be happy to do it. – William Hilsum Nov 14 '09 at 21:51

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