Web browsing on Mac slows down after a few days of use

When trying to browse any website, such as nytimes.com, yahoo.com, etc, it take sometimes anywhere from 15s-120s for the page to display. For example, in Chrome, when I browse to nytimes.com, in the status bar, I see the message "waiting for css.nytimes.com" or "waiting for www.nytimes.com" for a long period of time.

This is happening at home (on VPN to my employer's network or off) as well as when I'm connected to my employer's network directly. The problem occurs on all browsers on my Mac [Chrome, Safari, Firefox] and the curl command line tool in Terminal.

This problem seems to be isolated to my Mac. For example, when I browse on my iPhone (or my Windows laptop or another Mac laptop) on my home network, performance is great. It's terrible on my Mac. So this is definitely an issue with my Mac (OS Mountain Lion). This seems to be isolated to HTTP/HTTPS and not all TCP traffic since I can use SSH/RDP w/o any issues.

Using Activity Monitor, I can see ample free RAM and CPU utilization is minimal. I noticed this problem a couple of weeks ago. A reboot clears it up and then after 2-3 days, browsing starts to slow down again. Some pages take minutes to appear (or some suddenly appear in a flash when I stop loading the page).

What can I do diagnose the cause?

Solution 1:

I have the Cisco AnyConnect agent installed, which is only used for VPN and not Web Filtering. Still, the acwebsecagent process is running and slowing down my web browsing.

To uninstall acwebsecagent, run: sudo /opt/cisco/anyconnect/bin/websecurity_uninstall.sh

Credit to this post for the above command.

Solution 2:

You didn't specify the brand of VPN software, but the process you cited leads us to the Cisco AnyConnect client. A quick search turned up a blog post tracing similar problems no the default install options for the Cisco AnyConnect client. THe punch line is that an uninstall then custom reinstall of that software seems to have cleared the problem up for several users.

Here is the post.

Hope this helps.