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Windows 7 x64, Dell Optiplex 990, 3 Dell monitors, everything else stock.

Two monitors are running off of the built in VGA and Display Port. I originally installed a Geforce 6200 to get the third monitor up. Works fine in Chrome and nothing else is slow. (office pc, so no gaming tests I suppose)

Firefox was REALLY slow and had blacked out parts unless you hovered over them. So I got rid of the card completely and installed/plugged in an EVGA UV+ 19. Now Firefox is great on the monitors that are NOT on the UV+, but slow and laggy on the one that is.

Drivers and Windows updates are current. Firefox is the latest, version 12.0, no extensions, just a brand new install of it. Safe mode does not help.

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Please tell which version of firedox you are usinf and also try to run firedox qith safe mode option. – avirk May 24 '12 at 15:38

Which version of FireFox are you running?

Have you tried upgrading to the latest version?

Are you running any heavy extensions?

I usually have issues with firefox if I've been running it constantly for 3 or 4 hours, then I have to close it and reopen it again. After experiencing this a few times I ended up moving to Chrome.

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