Upload speed 100% after restarting PC?

[Don Genero]

Hello,

My ISP is DSL Extreme (but the lines are owned by AT&T) OS is Windows Vista and bittorrent client is uTorrrent 1.7.5 and the vast majority of times when I'm not using my PC I put it to sleep. A few weeks ago my I noticed my upload speeds were 50% or less what they used to be so I tried power cycling my DSL modem and flushing my DNS cache without success; it was only after restarting my PC that my upload speeds returned to 100%. My question to the gurus of this forum is why is restarting my PC correcting my upload speeds issue and is there a way to correct the issue without restarting my PC? Thanks in advance!

[Switeck]

Try Ultima's Troubleshooting Guide:

http://forum.utorrent.com/viewtopic.php?id=15992

[2good2b]

maybe it's got to do with vistas new tcpip behaviour on huge pipes with high latency. Compound TCP (CTCP) is described here: http://www.microsoft.com/technet/community/columns/cableguy/cg1105.mspx

"To better utilize the bandwidth of TCP connections in these situations, the Next Generation TCP/IP stack includes Compound TCP (CTCP). CTCP more aggressively increases the send window for connections with large receive window sizes and large bandwidth-delay products. CTCP attempts to maximize throughput on these types of connections by monitoring delay variations and losses. CTCP also ensures that its behavior does not negatively impact other TCP connections."

netsh interface tcp set global congestionprovider=ctcp

enables it. if it doesn't improve your steadily growing speed loss then just disable it again with netsh interface tcp set global congestionprovider=none

[Don Genero]

@Switeck,

I checked out Ultima's excellent guide before posting here but no cigar! The odd thing is that this upload problem only began a few weeks ago and I've had the same PC, OS, router, DSL modem, ISP, bittorrent client etc. for months (since aprox. 02/2007).

@2good2b,

Are those commands I'm to put in the command prompt? OK I just answered my question by pasting:

netsh interface tcp set global congestionprovider=ctcp

Into my command prompt (cmd.exe) and the response I got was: OK. Thanks for the response and I'll get back in aprox. 24 hrs. and let you know if it pans out or not. I was beginning to suspect it was a recent Microsoft/Windows/Vista update that was the culpret which (if we're correct) took place around the second Tuesday of September. It's not like it's a big deal to restart my PC a couple times a day in order to have 100% upload speeds to my P2P buddies I just liked it better the way it was before ;-)

[Switeck]

Overloading the half open connection limit in Windows Vista (and XP sp2) will cause the computer to download+upload slower until networking connections are reset (ie: reset PC).

Is µTorrent's half open limit currently set higher than 4?

[Don Genero]

Thanks Switeck,

Preferences/Advanced

net.max_halfopen 8

Should I lower it to 4?

@2good2b

netsh interface tcp set global congestionprovider=ctcp

Didn't help any so I'll do what Switeck recommends.

[2good2b]

good to know! you are not playing movies or listening to music while running utorrent, are you? vista is rather touchy in regards to prioritizing the hardware involved in the above.

[Switeck]

Disabling Resolve IPs (in the Peers window, right-click) and DHT should reduce µTorrent's use of non-TCP packets. For marginal networking hardware and software, that usually helps.

[2good2b]

I am no Vista user and can't speak from experience but I saw this official Microsoft statement on the net in regards to playing music or video from your computer's hard drive or DVD (NOT from the internet):

# "Please note that some of what we are seeing is expected behavior, and some of it is not. In certain circumstances Windows Vista will trade off network performance in order to improve multimedia playback. This is by design."

# "The connection between media playback and networking is not immediately obvious. But as you know, the drivers involved in both activities run at extremely high priority. As a result, the network driver can cause media playback to degrade. This shows up to the user as things like popping and crackling during audio playback. Users generally hate this, hence the trade off."

http://blogs.zdnet.com/hardware/?p=724

http://blogs.zdnet.com/hardware/?p=702

that's why I asked Don Genero whether he uses multimedia devices while torrenting. :-)

[Don Genero]

@Switeck & 2good2b,

Thanks for the imput but so far nothing has panned out. If and when I figure out what is causing this strange behaviour I'll post it here. For now I can:

1. Stop placing my PC in sleep mode and instead just let it run continously or shut it down.

2. Continue to use sleep mode and reboot the PC when needing to upload via uTorrent.

Happy surfing!

don Genero