Inconsistent transfer speeds

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truffle00

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I currently have a setup with a 10/100 router/switch at the top level, connected to a gigabit switch, to which my computer and HTPC are connected. When I transfer files, it is almost always files that are several hundred MB to a couple GB each (basically, not a bunch of tiny files).

Sometimes my speeds are sustained at 80+ MB/sec, and the lowest "normal" sustained speeds I see are in the 30-40 MB/sec range. Maybe 25-30% of the time, though, I transfer at around 11 MB/sec, which is painful when I know I could be transferring files much more quickly.

What, exactly, is going on here? I know that 11 MB/sec is the upper limit for 100 mbit connections, indicating that the connection is sometimes limited to 100 mbit/sec. Coincidentally, this is the maximum speed on the router. I don't know very much about networking, but is it possible that my data normally just transfers through the gigabit switch, but sometimes goes through the router?
 
Yes. I am transferring from my computer (where I am ripping my DVDs) to the HTPC.
 
There's no reason the switch should be directing traffic to the router. I take it everything is a simple network, right? Nothing like DMZ's or anything...right?

If not, how are you trasfering the files? If you're using sftp or SMB, try going to ftp... you should see a nice boost.

Also, are you using onboard network adapters? If so, are you taxing your computer during the times of transfer? You may want to look into a separate NIC.
 
It is a simple network. Both computers are running Vista64.

I am transferring the files using copy and paste in Vista.

I am using onboard network adapters, and I am not taxing either one when transferring files. I am transferring from a Q6600 @ 3.3 GHz to an E6600 (is that right? anyway, the dual core) @ 3 GHz.

I am just more puzzled by the fact that I will sometimes transfer at 80 MB/sec on a 2 GB file (which cannot all be cached on the RAID card), and other times transfer at a speed that looks like it is limited to 100 mbit. I know that copying and pasting in Windows isn't the most efficient way of doing this, but if it is so bad, I should never be able to hit 80 MB/sec.
 
Vista has a "feature" which reduces network load when you're playing media. Were you playing any music or videos during the slow transfers?
 
Madwand said:
Vista has a "feature" which reduces network load when you're playing media. Were you playing any music or videos during the slow transfers?
Click to expand...

That was pre SP1 IIRC and only with WMP and its equivalents. I have heard about this yet never experienced it myself and I do ALOT of network SMB transfers.
 
Madwand said:
Vista has a "feature" which reduces network load when you're playing media. Were you playing any music or videos during the slow transfers?
Click to expand...

I don't know. I am transferring a file right now, though, and it is going at 11.2 MB/sec, and I do not have anything playing. Hmmm...
 
I know how your felling truffle00, I'm currently dealing with the same problem, even on an i7 processor, I myself am gonna get a intel NIC since i hear that the onboard realcrap on my motherboard sucks.
 
vista even AFTER sp1 had slow networking, try to run these ina dos window reboot after running both seperatly, i did this at work and things flew after
Cause:
Microsoft Windows Vista has auto-tuning enabled for TCP/IP which continually adjusts itself. It increases file transfer speed on the network but in some cases it may actually slow down everything which is accessing network. Auto-tuning also slows down network browsing of other machines on the network.

What is Auto-Tuning?
Microsoft TCP/IP stack supports Receive Window Auto-Tuning. Receive Window Auto-Tuning continually determines the optimal receive window size by measuring the bandwidth-delay product and the application retrieve rate. It adjusts the maximum receive window size based on changing network conditions. By default in Windows Vista Receive Window Auto-Tuning enables TCP window scaling which allows up to 16MB window size.
The TCP/IP stack monitors the connection and measures the current bandwidth delay for the connection and the application receive rate and adjusts the receive window size to optimum throughput.

Solution:
To disable auto-tuning:
Run command prompt as an Administrator.
Type: "netsh interface tcp set global autotuninglevel=disabled" (without quotes) and press enter.

You may also need to run this command:
netsh interface tcp set global rss=disabled

To enable auto-tuning:
Type: "netsh interface tcp set global autotuninglevel=normal" (without quotes) and press enter.

To view the current TCP settings:
Type: "netsh interface tcp show global" (without quotes) and press enter.
Click to expand...
 
Thanks guys, I'll try some of your suggestions out tomorrow. Hopefully that fixes it. I mean, I don't *need* the ultimate connection speed, but if I can get it, it pisses me off when I can't.
 
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