Fiddler slows down my browsers

Question

Working with fiddler on 2 pcs. On my better performing pc fiddler slows down both browsers (firefox and IE7) significantly.

any suggestions would be appreciated

thanks, Ido

Answer 1

I think it is just a function of what fiddler does.

Ultimately, Fiddler is a debugging tool and not something you should have running all the time. Debugging tools do generally cause the thing being debugged to run slower.

Answer 2

"slow", without further data, isn't enough to go on. Have you looked at the requests (right-click, choose properties) to see which part of processing is the long-running part?

The most likely explanation is that on the PC which is operating slowly, when Fiddler isn't running, you have IE's Tools / Internet Options / Connections / LAN Settings / "Automatically detect proxy settings" checked. If you uncheck that box, you will likely find that throughput through Fiddler improves dramatically.

Of course, there's some overhead in running a buffering proxy; you can improve performance by enabling streaming mode (if you're not doing breakpoint debugging); see http://www.fiddler2.com/fiddler/help/streaming.asp

You can also help constrain the memory consumed by Fiddler using the Filter's tab; check the "Keep only the most recent [#] sessions" at the bottom of the page.

Answer 3

I've found Fiddler a little slow as well and I've switched to using CharlesProxy instead: however, if you always have them running and have them logging all browser interactions, then they will make your machine slower (as all browser requests all go through the Fiddler/Charles Proxy system and be logged and use up memory).

Answer 4

I haphazzardly installed Fiddler to try to fix something it wouldn't fix anyway. Not only did I have to uninstall it to get my browser to operate correctly again, I had to remove its dangling registry keys.