Following on from my whinge the other day about how IE 8.0's developer toolbar is causing pages to hang, CPU to max out (50% on dual core). I have noticed on a few sites now since upgrading to Firefox 3.5.2 and Firebug 1.4.2 that I have similar problems.
I have just been to my football site www.hattrickheaven.com and was clicking some of the leagues down the sidebars and wondering why the pages were taking so long to load. I then went to Chrome and tried the same links and the pages loaded as fast as lightening. This made me wonder about Firebug and low and behold disabling Firebug stopped the delay and the pages loaded very quickly. I would like some other people to try the same thing if they have Firebug and let me know the results e.g try these links with Firebug enabled and with it disabled:
With Firebug disabled they should load pretty quickly however with Firebug enabled its taking anything up to 15 seconds! Also check the Task Manager and see what CPU level Firefox shows as mine shows 50%.
I don't know if this is something to do with something within my page that Firebug cannot handle but the only validation errors I have are missing ALT attributes.
So as a tip for slow loading sites I would suggest in both IE and Firefox disabling the developer toolbar and Firebug and seeing if that helps speed up the load times. It seems to have worked for a number of sites now which is a shame as both toolbars should be great add-ons if only they could work without slowing everything down.