Slow browsing/downloading over wifi yet fast bt, why?
September 3, 2011 12:31 AM   Subscribe

Wifi troubleshooting, I've tried everything I can think of, why am I getting such low speeds?

I can get wired connection speeds of around 5 Mbps on my router but the second I switch to wireless it drops to 0.5 Mbps. My roommate gets about 4.5 Mbps through the same wireless so I figured it must be my network adapter but when I take my laptop to school I can get 22 Mbps through the University's wireless

The REALLY bizarre thing is that when I use bittorrent I can download at 4 Mbps speeds no problem. Just when I browse it's extremely slow

Okay, here is my setup at home:
AT&T DSL, Siemens Speedstream 4100 modem, Belkin N600 Router (was using D-Link DIR-655 with same problems)

Laptop: Fairly new T510 running Win7 Pro (my roommate runs linux if that might make a difference) with Intel Centrino Advanced-N 6250 AGN w/WiMAX network adapter

So here are some of the things I have tried:
Updated drivers on laptop
Updated firmware on router
Put DSL modem into bridge mode
Bought a dual band router so I could get away from other wireless networks from the neighbors, same speeds on both 2.4 and 5 GHz bands (fairly crowded 2.4 GHz band but none of my neighbors use 5 GHz)
Checked the speeds in safe mode
Uninstalled access connections
I checked everywhere I could think of to see if windows was diverting power from the wireless adapter
I typically use chrome but I still get slow speeds in IE
I'm sure I've tried some other things that I just can't think of at the moment

I hope someone can help, this problem has been driving me crazy for months
posted by crashlanding to Computers & Internet (13 answers total) 1 user marked this as a favorite
Have you set the laptop to channel bonding mode?
posted by Rubbstone at 1:35 AM on September 3, 2011

You don't mention if it has ever worked properly before. Did something change or is this how it has been since day 1? It's worth knowing and would be my first question to you if we were face to face. I'll assume "no" is the answer.

You've eliminated the wireless router as an issue with your bittorrent.
You've eliminated signal strength issues (loose laptop antenna) with the University's network.
You've eliminated much of the OS with your bittorrent check.

Ergo, I presume your hardware is OK on both ends of the wireless link.

Nothing left but the OS. Time for checking it out with another OS.

Try a boot with a Ubuntu (or similar) live CD. Once you've convinced yourself that there is nothing inherently wrong with your machine, you can focus intensely on Win7. Personally, I think you've got enough info to make this assessment now. It's probably some aspect of Win7 and your router/wireless card setup.

A cheap alternative would be to borrow a USB wireless adapter and install/check it out.

( It's not unheard of to have browser issues. Do you have another browser to check? I know it sounds silly, but so does having this problem for so long, and really... IE? Ick. )

At this point, turning off stuff would be my approach. Firewall, Anti-virus, etc. The critical thing is to change something, assess its impact, and change it back. You've to to make the problem go away, come back and go away again to call it solved.

Not to put too fine a point on it, but keep accurate notes about what you are doing.

Not much help, I know, but really, Microsoft has been providing this kind of fun to millions of users for years, and I wish I had back 10% of the time I've spent debugging this kind of crap.

Good luck.
posted by FauxScot at 5:17 AM on September 3, 2011 [1 favorite]

nthing FauxScot's advice, plus one additional quick thing to try:

Many wireless adapters have their own drivers and Wi-Fi apps. If you're using one specific to your network adapter, switch to the one built in to Windows. If you're using the built-in app, get the Intel app.

You may also want to get Process Explorer from MS. It may be overkill, but you can get lots of information about what processes are doing what on your machine.
posted by Mad_Carew at 5:42 AM on September 3, 2011

If your wireless adapter works elsewhere, it's not the adapter (or Windows itself). If your wireless router works for other people, it's not the router. If bittorrent works but not http, it has to be something with HTTP. Like a proxy getting in the way.

Win 7 differentiates connection settings between the networks you are attached to, so my guess is there is some kind of proxy set up in your "home" network settings.
posted by gjc at 9:19 AM on September 3, 2011 [1 favorite]

What are you using to measure your download speed?
posted by scatter gather at 12:19 PM on September 3, 2011

Response by poster: I'm pretty sure the problem has been around since I got this laptop, last winter, but I'm not positive. I'm also using to test download speeds. I've used another service in the past as well, I forget what it was, but it showed it being slow as well.

I've tried things like turning off the firewall and the wireless security to no effect. I guess it does seem like a Windows problem but the fact that it works fine on other networks with no other changes bothers me.
posted by crashlanding at 12:38 PM on September 3, 2011

You could also download and install a network protocol analyzer like Ethereal, and record some packet streams to disk files as you do some surfing while having the problem. Then, open and analyze the recorded packet streams - often you'll find excessive TCP/IP resets, packet fragmentation, WPA token renegotiations, or other obvious problems, pointing you towards changes you can make in the Windows network stack or your router, to improve matters.
posted by paulsc at 2:11 AM on September 4, 2011

Try changing your DNS server. Google runs DNS at and

Also, you don't say that you've tried using the machine on a wired connection. If the problem persists while wired, you can eliminated wifi-related issues.
posted by pompomtom at 4:55 PM on September 4, 2011

Response by poster: Update: I had a friend running Win7 test the network and he was getting good speeds. I do have it set on 20 MHz bandwidth only so it isn't jumping between 20 and 40 MHz. I can no longer connect to the 5 GHz band but I think that's just due to my excessive fiddling with settings.

I went into system config. and shut off all non Windows services to no effect, then I shut off all of the running Windows services one by one and ran a speedtest (when it wasn't something that would knock out the wireless completely) and nothing improved the connection.

Then, due to paulsc's reccomendation I installed Wireshark (Ethereal wasn't installing) and it looks like I'm getting a large amount of packet fragmentation. Now I tried to read up on how to use this to diagnose the problem but network management is another language to me. So I scanned the packets while I ran a speedtest and then when I downloaded something (from Itunes)

During the Itunes download:
Line 192: Protocol TCP Length 66 Info 52781 > http [ACK] Seq=1 Ack=162611 Win=64981 Len=0 SLE=164025 SRE=165439
Line 193: Protocol HTTP Length 1468 Info Continuation or non-HTTP traffic
Line 194: Protocol TCP Length 66 Info [TCP Dup ACK 192#1] 52781 > http [ACK] Seq=1 Ack=162611 Win=64981 Len=0 SLE=164025 SRE=166853
Then it pretty much repeats those two lines another 10 times with the SRE changing and it saying [TCP Dup ACK 192#2]->[TCP Dup ACK 192#11]
followed by: Protocol HTTP Length 1468 Info [TCP Fast Retransmission] Continuation or non-HTTP traffic

It does that a lot during the download

During the speedtest it is similar only instead of "Continuation or non HTTP-traffic" it has Protocol TCP Info [TCP segment of a reassembled PDU]

I do not know what much of this means so if you need more information please let me know

On preview: I did say that I could get wired speeds of 5 Mbps :)
posted by crashlanding at 5:11 PM on September 4, 2011

Response by poster: The DNS suggestion worked for about a minute and then the speeds plummeted again.
posted by crashlanding at 5:32 PM on September 4, 2011

I am out of my depth in terms of telling you how to fix it (not a Windows 7 guy), but it may be that your MTU is set too high. If it's set too high, your stack of gear may be sending packets that are too long and causes them to fragment. This can happen when you have lots of elements in the stack, like if you're using PPOE.

I'd start by reading DSL Reports on how to find out how to tweak MTU:
posted by Mad_Carew at 5:43 PM on September 4, 2011

screwed up the link, so raw:
posted by Mad_Carew at 5:44 PM on September 4, 2011

Try adjusting using the netsh command. Look down this page for the "change mtu manually" walk through.
posted by white_devil at 11:22 AM on September 6, 2011

« Older Creating Methods of Analysis for Dummies   |   How to move automatically emails to a folder Newer »
This thread is closed to new comments.