Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I am copying a small number of large files between a Vista x64 SP1 workstation and a Windows 7 RC workstation. Windows says it will take 7 hours to copy 117GB of data from one computer to another over an uncongested 1 GBit/s switch. Robocopy isn't doing much better.

I seem to remember from my Exchange days, that there were several utilities that claimed to copy very large files between servers. Are these utilities still available and if so, which are most effective in the above situation?


I am trying a Robocopy to a USB 2.0 external HDD, as this is all I have available at the moment and it is faster, this is unusual, as the two computers I am using are the only two computers connected to this particular 1GBit/s switch.

Edit 2:

Seems to be some problem with the NIC on the source, can't get the throughput above 3MB/sec after swapping everything else out. As this is the old machine I switched to using the external HDD which copied faster than the NIC, however it still took 3 and a half hours in total.

share|improve this question

13 Answers 13

up vote 10 down vote accepted
117GB/7H = 4.6MB/s

Something is wrong here.

Check for disk fragmentation, network misusage, another program grinding the drive or faulty hardware; Windows w/1Gb network can saturate the bandwidth that 7200 SATA drive can provide, i.e. 60-70 MB/s

I might also suggest that you create yourself a nice scheduled task to transfer the file(s) overnight.

share|improve this answer
Disk fragmentation is below 3%, target machine is a new build. Both PCs connected to 1Gb unmanaged switch with a third uplink to a 1Gb switch, I presume the switch should just route from one port to the other. No errors reported in the event log to suggest hardware problem, any other diagnostic thoughts? – Richard Slater May 11 '09 at 12:45
look at the network utilization, does it look capped? it should roam above 50%. run a disk diagnostic with hdtach or similar utility. Also look at the cables - dodgy cat5 cabling can mess up the transfer rate; if you can, try quality shielded cat6 cable. – Dani May 11 '09 at 12:54
Seems to be some problem with the NIC on the source, can't get the throughput above 3MB/sec after swapping everything else out. Dosn't matter as this is the old machine. – Richard Slater May 11 '09 at 14:46
Good catch on the throughput red flag! +1 – squillman May 11 '09 at 15:22
how did you check the throughput? – Svish Jun 8 '09 at 7:46

For something that large and considering it's a local copy I would either plug the hard drive of one of those PCs into the other and do a direct copy. Alternatively I would use an eSATA hard drive to do the transfer. That's going to be way faster than even GigE.

That all assumes this is a once off, which is how I read your post.

share|improve this answer
I'm not sure that eSATA would be faster than 1G; you can read and write simultaneously and as I said (and witnessed), 1G provide enough headroom in terms of bandwidth for a 7200RPM drives – Dani May 11 '09 at 9:52
@cletus: 'way faster'? 7200RPM 3,5" HDD have write speeds of 70-90MB/s. 1GBit/s is 125MB/s, even if you take in account protocol overhead, it's more then enough. – vartec May 11 '09 at 10:57
Hard drives top out over 100MB/s,2845,2173845,00.asp and you won't get that out of GigE. – cletus May 11 '09 at 12:12
yes, but you're missing on the concurrent read/write of the network vs. eSATA which halves the effective throughput – Dani May 11 '09 at 12:20
@cletus: that's read speed. writes are a lot slower. – vartec May 11 '09 at 14:25

Well, it should take about half an hour to copy that.

Anyway, how long did you wait before canceling it? Did you take a look at the details, to check actual copy speed? Vista's initial estimates are very often way off. After a while it recalculates the speed to give you better estimate.

share|improve this answer
I waited about 40 minutes, while I did something else that was when it said 7 hours. Something along here is wrong, not sure as yet what it is. – Richard Slater May 11 '09 at 12:42
clearly something else then. net drivers on either side? – vartec May 11 '09 at 16:27

Here's a tip that says that disabling the network stack's receive-window-auto-tuning may fix your problem. Run As Administrator:

netsh int tcp set global autotuninglevel=disabled

You may also want to consider enabling jumbo frames (9000 bytes MTU) on each system to see if that helps.

share|improve this answer

I have heard of this happening with a lot of people using vista to copy over the network.

I did a quick google search to verify. There a lot of "fixes" listed here.

This article explains the Vista SP1 file copy improvements and why it works the way it does.

share|improve this answer
Thanks, running Vista SP1 on the source and migrating to Windows 7 seems that the NIC is bust. – Richard Slater May 11 '09 at 14:52

I've seen slow copy performace over ipv6, especially over wireless, as a test did you try disabling ipv6 just as test?

you could be running into the vista performance problems, smb2 probs, differential network copy etc, I think there are bugs somewhere in those also

also try teracopy, it optimizes the transfer

share|improve this answer

I would consider using SyncBack. We use it to move up to 30 GB files over WAN with reasonable throughput for off-site backups. There are different versions of it some of which allow throttling the use of bandwidth, using native versus Windows copy and FTP.

share|improve this answer

There is a protocol for transferring files. It's called FTP. You may find that this works better for you than using network shares. (although other posters are right that you should get better throughput that you are doing over the network).

share|improve this answer
mmm... heard of FTP once, someone mentioned it was something to do with broken Cat5 cable though, so I dismissed it ;) – Richard Slater May 11 '09 at 14:53

The best file copy utility by far is Teracopy, from I've been using it for years with XP, and find it works just as well in Vista. I agree with the other posters that something else is probably wrong in this situation, but to answer the original question, teracopy FTW.

share|improve this answer

I've found that a single-threaded file copy tops out at around 40Mb/sec - consider using richcopy to do a multithreaded transfer.

share|improve this answer
robocopy under Windows 7 and Windows 2008 R2 support multi-threaded transfer with the /MT switch uses 8 threads by default. – Richard Slater May 18 '09 at 18:45

The Exchange utility you're thinking of is probably esefile, the functionality of which has now been baked into the eseutil utility. "eseutil /y" is the switch you use. I haven't tested it against robocopy or the Vista copy utility, so I don't know if it actually still provides a speed advantage.

share|improve this answer

Try testing the raw TCP performance with a point to point TCP benchmark. Everest has one for example. Or write a 10 line script.

Fast TCP => NIC is not broken

Slow TCP => It is not SMB-related. FTP wont help either

share|improve this answer

Use robocopy from the command line (including with Vista/Win7). This will provide progress reports and the ability to filter what is copied (and not copy files that have not changed).

share|improve this answer
I have been using Robocopy, unfortunatly it is no faster than Vista's copy UI. – Richard Slater May 11 '09 at 12:40

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.