Most virus checkers have real-time protection enabled. I find the file virus checker in Firefox 3 to do no more than slow my computer down. Learn how to disable the automatic virus check in Firefox 3 in this guide.
Disable Virus Auto-check in Firefox 3
Please be sure you are downloading safe files. This virus check is put in for a reason and should only be disabled if you are confident you know what you are doing.
- Type about:config in the Firefox address bar
- Now filter the following browser.download.manager.scanWhenDone
- Set the parameter to False
Now, Firefox wont slow down after every file you download.