Vista Patch Improves 3G WWAN Card Performance

ginggs

ginggs

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I found a link to this page on the Novatel Wireless website on the Xu870 support page, I don't recall seeing any mention of it on mybroadband.

Microsoft Knowledge Base article KB940646
Transmission throughput is less than expected for a 3G WWAN data card in Windows Vista

SYMPTOMS
You use a 3G wireless wide area network (WWAN) data card on a Windows Vista-based computer. The WWAN data card uses a connection that only receives data. However, you may find that the throughput is much less than the throughput of the same 3G WWAN data card when you use it on a Microsoft Windows XP-based computer.

CAUSE
This problem occurs because of the way that TCP receive window auto tuning is used in Windows Vista for connections that only receive data.

Windows Vista obtains a round-trip time (RTT) estimate at the time of connection setup and every time that a new segment of data that is transmitted. A connection that only receives data is limited to the single RTT sample that is obtained at the time of connection setup. Because the connection only receives data, the connection cannot "converge" to the actual RTT of the connection. For example, because the RTT data may fluctuate for various reasons, a "converge" operation is performed to estimate a meaningful RTT by using blending current and previous RTT data. However, if the connection cannot converge to the actual RTT of the connection, the bandwidth delay product (BDP) estimate that Vista obtains is also incorrect. Therefore, the connection's receive window is limited, and throughput of the connected transmission network is reduced.
Click to expand...
 
This is quite important. Thanks ginggs.

Any feedback from Vista users will be great, but first run a batch of performance tests to speed.vodacom.co.za before applying the patch and then again afterwards.
 
It might actually make a difference...

Option GT MAX 3.6. PPDB internet APN. Vista Business

Started 20:40 - pre update
Download Speed: 2236 kbps (279.5 KB/sec transfer rate)
Upload Speed: 293 kbps (36.6 KB/sec transfer rate)

Download Speed: 2341 kbps (292.6 KB/sec transfer rate)
Upload Speed: 334 kbps (41.8 KB/sec transfer rate)

Download Speed: 2256 kbps (282 KB/sec transfer rate)
Upload Speed: 342 kbps (42.8 KB/sec transfer rate)

Download Speed: 1938 kbps (242.3 KB/sec transfer rate)
Upload Speed: 322 kbps (40.3 KB/sec transfer rate)

Started 21:00 - post update
Download Speed: 2682 kbps (335.3 KB/sec transfer rate)
Upload Speed: 337 kbps (42.1 KB/sec transfer rate)

Download Speed: 1994 kbps (249.3 KB/sec transfer rate)
Upload Speed: 301 kbps (37.6 KB/sec transfer rate)

Download Speed: 2543 kbps (317.9 KB/sec transfer rate)
Upload Speed: 350 kbps (43.8 KB/sec transfer rate)

Download Speed: 2759 kbps (344.9 KB/sec transfer rate)
Upload Speed: 347 kbps (43.4 KB/sec transfer rate)

The second round is probably some of the best speeds I have ever clocked. While I am still pessimistic about this patch having any effect I don't think you have anything to loose by loading it (except some time). This patch takes a while to install. It took me almost 10min from start to finish. Ran the installer, Start the reboot, wait for pre-shutdown updates, then reboot wait for pre-startup updates login, wait for windows to finish exercising my hard disc and then finally on to the speed tests :eek:

Edit: PS. How are we coming along with that suggestion of not deducting data for doing speed tests... They all add up in the end you know ;)
 
Last edited:
Will Vodacom make this Patch Available, or is it included with the Windows Updates?
 
Iam3G said:
Will Vodacom make this Patch Available, or is it included with the Windows Updates?
Click to expand...
It's mostly security updates that are made available through Windows Update, it will probably be included in Vista SP1 though.
 
morkhans said:
Option GT MAX 3.6. PPDB internet APN. Vista Business

Started 20:40 - pre update
Download Speed: 2236 kbps (279.5 KB/sec transfer rate)
Upload Speed: 293 kbps (36.6 KB/sec transfer rate)

Download Speed: 2341 kbps (292.6 KB/sec transfer rate)
Upload Speed: 334 kbps (41.8 KB/sec transfer rate)

Download Speed: 2256 kbps (282 KB/sec transfer rate)
Upload Speed: 342 kbps (42.8 KB/sec transfer rate)

Download Speed: 1938 kbps (242.3 KB/sec transfer rate)
Upload Speed: 322 kbps (40.3 KB/sec transfer rate)

Started 21:00 - post update
Download Speed: 2682 kbps (335.3 KB/sec transfer rate)
Upload Speed: 337 kbps (42.1 KB/sec transfer rate)

Download Speed: 1994 kbps (249.3 KB/sec transfer rate)
Upload Speed: 301 kbps (37.6 KB/sec transfer rate)

Download Speed: 2543 kbps (317.9 KB/sec transfer rate)
Upload Speed: 350 kbps (43.8 KB/sec transfer rate)

Download Speed: 2759 kbps (344.9 KB/sec transfer rate)
Upload Speed: 347 kbps (43.4 KB/sec transfer rate)

The second round is probably some of the best speeds I have ever clocked. While I am still pessimistic about this patch having any effect I don't think you have anything to loose by loading it (except some time). This patch takes a while to install. It took me almost 10min from start to finish. Ran the installer, Start the reboot, wait for pre-shutdown updates, then reboot wait for pre-startup updates login, wait for windows to finish exercising my hard disc and then finally on to the speed tests :eek:

Edit: PS. How are we coming along with that suggestion of not deducting data for doing speed tests... They all add up in the end you know ;)
Click to expand...

Good feedback, thanks.

I've been thinking on doing some testing on TCP window sizes for a while as it will affect throughput, especially with larger files and higher speeds.
 
vodacom3g said:
Good feedback, thanks.

I've been thinking on doing some testing on TCP window sizes for a while as it will affect throughput, especially with larger files and higher speeds.
Click to expand...

Pleasure.

You are running Vista as well if I recall or did you get rid of it? Will you be doing some tests as well? Will be interesting to see if it makes any difference to your WiMax speeds as well.
 
Speed test results prior to the installation of "Windows6.0-KB940646-x86.msu"​

[Using speed.vodacom.co.za:]
Download speed: 1449kbits/s
Upload speed: 338kbits/s

Download speed: 1038kbits/s
Upload speed: 338kbits/s

Download speed: 825kbits/s
Upload speed: 317kbits/s

Download speed: 1999kbits/s
Upload speed: 325kbits/s

Download speed: 1798kbits/s
Upload speed: 261kbits/s

[Using speedtest.net, Jhb server:]
Download speed: 1946kbits/s
Upload speed: 329kbits/s
Ping: 272ms
Click to expand...
Download speed: 2079kbits/s
Upload speed: 335kbits/s
Ping: 288ms
Click to expand...
 
morkhans said:
Pleasure.

You are running Vista as well if I recall or did you get rid of it? Will you be doing some tests as well? Will be interesting to see if it makes any difference to your WiMax speeds as well.
Click to expand...

I run Vista on my desktop, XP on my laptop but the radio conditions at home will be the limiting factor. I get about 1.4Mb/s.

So I'm cautious to test if the radio conditions could skew the results.
 
vodacom3g said:
I run Vista on my desktop, XP on my laptop but the radio conditions at home will be the limiting factor. I get about 1.4Mb/s.

So I'm cautious to test if the radio conditions could skew the results.
Click to expand...

You should get the Vodacom guys to fix that :p
 
vodacom3g said:
The "Vodacom guys" tend to look well after me. :)

I got a 3G extender a while ago and that worked well but I'm waiting for a new model that support 3.6.
Click to expand...

You should get them to bump you to 7.2 while they are at it :cool:
 
Wonder if this patch is built into SP1?

I've never had problems, get up to 2.8 at home on my new Dell 630C w/5520 running SP1 (release). Few weeks ago I saw 3.1 on my old D620 w/5520 running SP1 RC at VodaWorld.
 
Speed test results after the installation of "Windows6.0-KB940646-x86.msu"​

[Using speed.vodacom.co.za:]
Download speed: 1855kbits/s
Upload speed: 259kbits/s

Download speed: 1404kbits/s
Upload speed: 344kbits/s

Download speed: 1603kbits/s
Upload speed: 336kbits/s

Download speed: 1485kbits/s
Upload speed: 156kbits/s

Download speed: 1120kbits/s
Upload speed: 321kbits/s

[Using speedtest.net, Jhb server:]
Download speed: 2402kbits/s
Upload speed: 341kbits/s
Latency: 294ms
Click to expand...
Download speed: 1918kbits/s
Upload speed: 322kbits/s
Latency: 270ms
Click to expand...
 
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