Web site slow in Firefox, works great in Chrome. All other sites fine in Firefox. XP SP3, Firefox 3.6.3, Chrome 4.1

Dell Precision T3400 running XP SP3 all patches current. I'm having an issue that I can't figure out, and am looking for some further trouble shooting steps or ideas of what is happening. Firefox on this system can access all websites including our live site with no speed problems, but runs super slow when it connects to the test version of my live site. Chrome on the same system runs fine when connecting to the test site. I have tried deleting all cached info in Firefox, creating a new profile, creating a new user, site still runs slow. Disabled all add-ons in firefox except needed, site runs slow still. I'm at a loss for an explanation or what to try next. Some other points.....
1. My test site loads fine on 100s of other systems using Firefox.
2. Live site is an exact copy of my test site, but runs fine in Firefox on the problem system.
3. Doesn't seem to be a TCP issue because Chrome works
4. Doesn't seem to be a Firefox issue because all new accounts with clean settings still have the problem.
5. I've rebooted, cleared all network settings/caches and temp files.
6. No idea what else could cause this issue.
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Dave BaldwinFixer of ProblemsCommented:
Can you post the URL of the problem site.  It's hard to help you without that info.
adamant40Author Commented:
Sorry, it is an internally accessible only site. And the site is working fine for 200 other systems. My problem is that I can not come up with a theory that fits one browser working and one not, must be a hole in my understanding of TCP/IP and troubleshooting. So I'm mostly looking for ideas on what would cause the difference in the 2 browsers, eliminating all the standard stuff of Profiles, Add-Ons, Proxy Servers, DNS, etc. Problem is definitly on this one machine, one browser, one site.
Dave BaldwinFixer of ProblemsCommented:
Firefox will display some errors if you press Ctl-Shift-J.  Each of the browsers has a slightly different javascript engine and different ways of handling errors.  And it;'s my experience that no two web servers are exactly the same either.  I have a minor problem on this machine with Firefox 3.6.3 because it keeps using more and more memory the longer that it runs.  Firefox also connects with Google to check for 'safe browsing' but I don't know what triggers that.
adamant40Author Commented:
traced the problem to a Skype Add-On in Firefox. Disabling that fixed my test site speed.  I was momentarily puzzled why this wasn't affecting my live site until I realized that it was being hit through the firewall. I used HOSTS entries to use the internal IPs (bypassing the firewall) and my live site also ran slow with the Skype add-on installed.  So while I have an answer to my first quetion, I'd love to know what is different and would cause this problem inside my firewall, but not from the exact same server outside my firewall. Frame size? This is a hole in my knowledge level. I'll leave this open for a few days and assign points to anyone who can give me insite into the reason this happens.  

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