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Internet Speed Fluctuations

Sun Guru

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I have posted this question on another forum and I though that maybe someone here can help me as well.

Hi there...

I have a very technical problem and hope that someone here could help me with it.

I have a 100Mbps connection and I can seed at 10 MB/s easily. Lately I have been having a little bit of problem with my internet connection. It seems to me that my connection is very unstable. As you can see from the pictures that I have attached below,my connection reaches 25 % of it's capability and then suddenly drops to 1% and then goes back to 25% and then back to 1%. This sequence happens every second. This behavior is also displayed by my Utorrent speed graph. Then I thought that my university is doing some speed capping but I phoned a friend of mine who works there and he told me that that is not the case and that his connection is still at full speed. He told me that is the uni wanted to cap only my speed that he would have been notified.




Extra Info

It is not my Network Card because I have just bought a new one, but the problem persist.

It is not my connection because it works just fine in the other rooms of the building. ISP speed capping I have already ruled out when I called them for info.

I don't have a router. It's a direct permanent connection.

Desktop XP Anthlon 2800+ 1.8 GHz 1 GB ram.

Again, I have a 100Mbps connection and I could easily upload at 10 MB/s. Since this problem started I can only reach 2 MB/s or around 25 % of my connection capacity.

When I start Utorrent all seems to go allright, and after a minute or two, this fluctuating trend begins.

Global maximum connections is set to 2000

Maximum number of connected peers per torrent is set to 250

Number of upload slots per torrent is 75

Anymore info's?

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Your line may be able to handle all the connections, but possibly something on your computer can't.

Have you tried with connection max (and per-torrent) reduced to only 100?

What is your half open limit set to in µTorrent?

(Did you patch Windows and everything network-wise to handle any changes you made to half-open limit?)

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@ Ultima...I have tried that but it did not work. Again, the fluctuations began when it was nearing 2 MB/s.

@ Switeck...net.max half open is set to *4. I have already tried upping it to *8, but it didn't do anything. TCPIP.sys is patched at 50....

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What I have noticed is that Process Explorer also tell me the the I/O bytes usage for Utorrent fluctuates in sync with the speed fluctuations.

But other than that, I don't see anything abnormal. Could you please tell me exactly what kind of diagnosis you need from Process Explorer?

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  • 2 weeks later...

Process PID CPU Description Company Name

System Idle Process 0 81.54

Interrupts n/a Hardware Interrupts

DPCs n/a 7.69 Deferred Procedure Calls

System 4

smss.exe 656 Windows NT Session Manager Microsoft Corporation

csrss.exe 716 1.54 Client Server Runtime Process Microsoft Corporation

winlogon.exe 740 Windows NT Logon Application Microsoft Corporation

services.exe 788 1.54 Services and Controller app Microsoft Corporation

svchost.exe 960 Generic Host Process for Win32 Services Microsoft Corporation

livecall.exe 3188 Windows Live Call Microsoft Corporation

svchost.exe 1008 Generic Host Process for Win32 Services Microsoft Corporation

svchost.exe 1068 Generic Host Process for Win32 Services Microsoft Corporation

svchost.exe 1180 Generic Host Process for Win32 Services Microsoft Corporation

svchost.exe 1324 Generic Host Process for Win32 Services Microsoft Corporation

spoolsv.exe 1496 Spooler SubSystem App Microsoft Corporation

AppleMobileDeviceService.exe 368 Apple Mobile Device Service Apple, Inc.

avp.exe 464 Kaspersky Anti-Virus Kaspersky Lab

MDM.EXE 528 Machine Debug Manager Microsoft Corporation

svchost.exe 1216 Generic Host Process for Win32 Services Microsoft Corporation

alg.exe 2924 Application Layer Gateway Service Microsoft Corporation

usnsvc.exe 3316 Messenger Sharing USN Journal Reader Service Microsoft Corporation

lsass.exe 800 LSA Shell (Export Version) Microsoft Corporation

explorer.exe 1748 Windows Explorer Microsoft Corporation

soundman.exe 1888 Realtek Sound Manager Realtek Semiconductor Corp.

avp.exe 1896 Kaspersky Anti-Virus Kaspersky Lab


realsched.exe 1920 RealNetworks Scheduler RealNetworks, Inc.

msnmsgr.exe 2004 Messenger Microsoft Corporation

wlmail.exe 2432 Windows Live Mail desktop Microsoft Corporation

ctfmon.exe 2016 CTF Loader Microsoft Corporation

DesktopWeather.exe 2028 The Weather Channel Interactive

firefox.exe 1956 Firefox Mozilla Corporation

procexp.exe 864 3.08 Sysinternals Process Explorer Sysinternals

utorrent.exe 3880 4.62


This is the file of processs explorer when it's fluctuating.

I think that I have ruled out hard drive problems because running torrent on either of my three HD's causes this fluctuations.

I have also ruled out AV problems. Just installed a new AV.


I keep seeing that once it hits 2 MB/s, the fluctuations starts. Limiting my speed to 1400 KB/s and the connection is steady. Any above that and it will begin fluctuating again.

Help please! Sure that it's a waste of my 10 MB/s uploading capacity!

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  • 3 weeks later...

Sun Guru...

I've been having the exact same problem as you for the past couple of days, did you find a solution?

I also have a 100Mbps connection, the only difference is my utorrent speed graph fluctuations are much more pronounced than you. It goes from like 2mbps to almost 0 and then goes back up every 15-20 seconds or so.

I've had these problems ever since I changed my motherboard, ram and graphics cards last week. I'm sure it's related but I can't see how... anybody?

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Since it fluctuates in one second intervals, as you have described, it seems as though something is connecting to the internet once every second. Since you seem quite computer apt, I'll suggest a couple steps to double check this. Close MSN Messenger and see if it still fluctuates. If it does (which it presumably should), close µTorrent and start WireShark. Capture traffic for about 30-60 seconds, and look for any repetitive traffic. If you find anything, try to figure out the source of the traffic. One other possibility is that somebody is trying to DoS you, though I doubt it. If they are, WireShark will pick up on the traffic. If one of these isn't the case, it's possible that something is repeatedly accessing your hard drives.

If you have a friend with a laptop (or easy to transport computer) who could help you, try connecting their computer to your internet connection, and test it on their computer. That will pretty much determine whether the problem is with the network, or your computer.

EDIT: Hey, dead thread. Meh, same general suggestions apply to Blucka.

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TCP View (from www.sysinternals.com ...now taken over by Microsoft, but the download is still available) will not only show if there's other connections to your computer outside µTorrent...on Win XP it will even show WHAT program is making them!

...Which should prove a little quicker of a check than running WireShark and trying to read through 30-60 seconds worth of traffic on a 100 megabits/sec line. :lol:

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I have tried closing msn already...

But I should say that there is a huge progress today. Again I asked for a neighbour of mine to lend me his laptop so I can run Utorrent on it...and voila! There I see the fluctuations again.

That was the proof I needed to contact the ISP. They came to my appartment within 10 minutes of calling them. The guy tried downloading a file from a GB/s network and to his surprise it got stuck again at the 17% mark of the fluctuations. I told him that it was the same as the other guys' laptop and he told me that he still isn't convinced that it is NOT my PC. he told me he would come around with his own laptop...

and btw...this is NOT a dead thread. It's simply that I cannot double post to revive it.

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Many Win XP/98/NT/2k and probably everything short of Vista running computers are often NOT optimized to run at very high speeds if their latency is over 100 milliseconds (ms). They're set up for sub-ms speed 100 megabits/sec and faster office LANs. So just because more than 1 computer failed doesn't instantly mean there's something wrong with the line.

Have you tried TCP Optimizer from here?


Be very careful when reading the instructions or you can inadvertently Denial-of-Service your own connection with extreme settings...fixed by re-running TCP Optimizer and reseting some settings and rebooting. Win XP SP2 boxes won't handle having 10+ connections going to 1 server at once nicely without patching the half open limit way above the default of 10.

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With a lost=1 only, that could be just "bad luck" for that 1 packet.

However, an average time of 104 ms seems a bit high...especially for a very fast internet connection.

...Unless you're in Asia and GOOGLE is in North America, then it might still make sense.

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