Webpages load much slower on Linux than Windows

[gavinhc]

For about a month now I've been experiencing very slow loading time for webpages on my both my Linux installs (LMDE tracking testing and Arch). But, my Windows XP install on the same machine loads pages much faster.

First, a little background:
- I've had the same LMDE install for almost a year and a half and it is only in the last month I've experienced the slow loading times online, implying it is a recent change that caused this.
- My desktop, where I'm experiencing this, is connected via ethernet. My motherboard has an onboard Atheros ethernet controller.
- I did some testing yesterday, and loading a set of pages on Windows took about 3-5 seconds each. Loading the same pages on both LMDE and Arch took between 30 and 60 seconds. Whatever is causing this, it is happening across both Linux installs and is not specific to a single distro.

Since this problem showed up recently and affects both Arch and LMDE, my only thought is that something software package was updated about a month ago that caused this. Are the Atheros drivers part of the Linux kernel? If so, could they have been updated (broken?) in a kernel update? Unfortunately, I am unsure where to go from here. There has always been a gaping, networking-shaped hole in my technical knowledge, so I do not know how to even diagnose the problem beyond what I've already done.

[craigevil]

Using the same browser an version of all OSes?
Do both linux systems have the same kernel version?

Is it slow in all browsers? Firefox, Chrome, Opera etc. Are the browsers the same versions?

If you use Firefox try on a clean profile. Or in safe-mode.

You could try disabling ipv6.

[gavinhc]

Each Linux system is currently running a different version of the kernel. Today LMDE is on 3.2.15 and Arch is on 3.3.3, on the weekend when I ran my tests Arch was on 3.3.2. There doesn't appear to be an improvement in the internet speeds on Arch since the upgrade. I have been experiencing this since at least version 3.2.12 on Arch, I do not recall which version LMDE was on when I first noticed the slower speeds.

It is slow in both Chrome/Chromium and Firefox. I haven't tried Opera, although I would guess it would be the same. It is also slow loading images in my RSS reader (RSSOwl, which I believe uses the XULRunner for its backend) and both apt-get and pacman updates are running noticeably slower than they used to. So, I think it is a lower-level system issue and not specific to any one program.

I should note (I forgot to mention this in my previous post) that it appears that the slowdown is in actually negotiating a connection with a website/server. If I am downloading a large file through the browser, it can take up to a minute to start the download, but once it starts it downloads at my ISP's advertised speed of 20 Mb/s. Same thing with streaming video on YouTube, it takes a long time to start playing a video, but once it does I have no trouble keeping up with buffering at 720p.

I have never explicitly enabled IPv6 in any of my OS installs, although the Arch wiki says that it has been built into their builds of the kernel directly since 3.2.6, so it is probably enabled there. I cannot find as clear information about it on the Debian wiki, but it does say that IPv6 support was a release goal for Squeeze. Since I have had the same LMDE install since January 2011 and the internet slowdowns have only happened in the last few weeks to a month, I am uncertain if IPv6 is to blame, but I will try disabling it to see if it makes any difference and report back.

Thanks for your help, if you have any other ideas, I'm open to them!

[craigevil]

Have you tried using OpenDNS or Google's DNS servers instead of your ISP's?

I find even with my router setup to use OpenDNS it still helps to have the nameservers in resolv.conf.

[gavinhc]

I finally had the time to sit down and work on this again.

In my Arch install, since that's the one I use mostly for testing/breaking things, I've tried disabling IPv6 on boot following the instructions here. From a fresh boot, I tried access the same series of websites I used in my testing last week to see if there was any change in the loading times. For some of the pages, I saw a bit of an improvement (e.g. 21 seconds loading times instead of the 32 last weekend), but for others I saw things go even slower (e.g. 75 seconds today, 57 seconds last weekend). Since my testing is entirely unscientific (measuring loading times with a stop watch, nowhere near statistical sample sizes, etc), I'm not convinced these changes are outside the margin of error.

I have not yet fiddled with my DNS settings in my router since everything is working fine with my Windows and Mac OS installs and I don't want to risk breaking those too. Also, I can't seem to remember the login information to access my router at the moment. I don't suppose that simply changing the DNS server in my OS settings would have any effect if the router's DNS settings are still pointing to my ISP's defaults?