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JulienVanFlag for France

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Windows limits download speed at 65 kb/s

Hello,

All files that I download under Windows XP on my laptop are limited in speed to 65 kb/s.
I can download 1 or 20 files, the download speed is always between 60 kb/s and 70 kb/s for each file.

I was thinking that it came from my Internet access provider firewall, but when I download files on the same computer, with the same browser (Mozilla Firefox), under Ubuntu, the download speed increases to 300 kb/s.

Would you know how I can increase the download speed limit under Windows XP?

Thank you,
Julien
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John
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>Would you know how I can increase the download speed limit under Windows XP?
The default TCP/IP settings/prarmeters in WindowXP (Assuming you have not tweaked anything) can affect your dowload/upload performance depending BDP, RWIN, and other factors:

http://www.speedguide.net/read_articles.php?id=157
http://www.speedguide.net/tcpoptimizer.php

Please be very cautious in the WIndows registry and backup the registry before you attempt any registry modification.

Billy
Windows XP was very well refined at setting up these parameters (tweaking them went out with much older systems). So unless they have been misadjusted, they should be fine. .... Thinkpads_User
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csalaski

Agreed, the XP defaults are generally totally fine, yet, the pc performs significantly better under Linux indicating windows settings or driver if your suggestions do not clear the problem.
>Agreed, the XP defaults are generally totally fine, yet, the pc performs significantly better under Linux indicating windows settings or driver if your suggestions do not clear the problem.

unfortunately I would have to disagree; Windows 2000 and XP, both are generally better optimized for networking than Windows 9x and even NT4. Regardless, both XP and 2000 are still configured with respect to Ethernet rather than high-speed Internet connections, where latency plays a major role in throughput. Windows XP does not have any type of Receive Window Auto-Tuning; so depending on the latency and RWIN values, it can affect bandwidth performance. Tis, why when you use Linux it works to your expectations (Linux has had TCP autotuning for years!).

http://technet.microsoft.com/en-us/magazine/2007.01.cableguy.aspx
http://www.psc.edu/networking/projects/tcptune/#WindowsXP

Obviously before an attempt is made to the registry that all other resources have been exhausted and only if there is evidence that the default TCP values is what is causing the issue.

Can you post the output from this site: http://www.speedguide.net/analyzer.php
This will be used to analyze the data later on for a diagnose.

What is your ISP Connection bandwidth?
Is the slow download for all sites your download from?
When you say 65 kb/s, are you aware of the difference between 65Kbps and 65KBps, lowercase b and uppercase B have 2 different meanings. 65Kbps and 300Kbps is still rather slow depending on the current bandwdith utilization and/or the CIR (Commited Information Rate) from your ISP.

Billy
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Hello everyone, thanks for your suggestions.

@Thinkpads_User: I clean regularly my temporary files, the browser cache is set by default at 50 Mb, I'm using DHCP, but my DNS addresses are set automatically. Do I have to define a custom DNS server address?
For the system and hardware upgrades, I've the last ones.

My computer is a HP 6730b with Windows XP SP3, 3 Gb memory, and the last network drivers downloaded from HP support website.
I have a decently fast broadband connection at my home office from my ISP  8Mbits/sec download when I had XP and it is 10Mbits/sec now I have Windows 7. I never had the kind of limitation described here with XP and never had to change the Receive Window or any other parameter. YMMV. ... Thinkpads_User
JulienVan - If your DNS is working, you probably do not need to change it.

I am not sure what else, because you are saying Ubuntu on the same computer and so the same router (my assumption from above) is faster.

Is your connection DSL?  And if so, consider looking at the MTU in the router. It will default to 1500 and works better at 1492 (sometimes a bit lower) on DSL. One would think that might affect Ubuntu as well, but it is worth a look ... Thinkpads_User
@Billy: I was not aware about the difference between kb and kB because it is displayed in Mo on my french OS, but I was talking about kBytes/s

I'm enclosing the results of speedguide.net analyzer and speedtest.net, what do you think about it?

Maybe I can test to change the RWIN value in registry.
speedguide.jpg
speedtest.jpg
Your upload looks about right, but your download is very slow. Are you sure you don't have an ISP problem?
... Thinkpads_User
Your default RWIN is 17424 with no support for RFC1323

So if you have 200ms of latency round trip you will only get 87KBps of download or if you have 500ms you can expect at least 35KBps; based on your ping time, your ping time is 424ms. So what you are seeing is based on the latency end to end. Very possible that you are saturating your bandwidth or there is an ISP issue that you are unaware.

Can you traceroute to a local server and report the output?
 
>Maybe I can test to change the RWIN value in registry.
I would wait at this point, you could change it to reflect your current latency, but as that changes, so does your performance; hence why TCP Autotuning was designed for Windows 2003 and recent OSes.

Billy
Hello guys,

I think that it doesn't come from my ISP because I haven't the problem with my second computer, and I've got the same problem with this computer when I'm connected outside of my home.

What do you think?

Can it be because of my Windows firewall? I cannot disable it to test without, because a message is displayed telling that firewall parameters are controlled by group policies.
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