I used up2date to update firefox to 1.0, and ever since then, Firefox is running really slowly, and when it's doing something, it causes all my other running programs to drag as well. I've tried running just Firefox, and it still drags, even when I used it in XFCE, which is much more lightweight, so I don't think it's a memory problem
Has anybody else seen this? If so, has anybody figured out how to fix it?

Run top and see what processes are running, memory usage, etc.
The first time I ran firefox, firefox-bin was running on 14 different ports! Don't know what caused it, I rebooted and it hasn't done it since.

I'm not having a problem with firefox-bin. It does look like I'm running a few processes more than usual, but not all my physical memory is being used up, and none of my swap is being used, so I don't think memory usage is the problem. I can't image what else it could be, though.
Some of the processes that seem to be running too many instances are 10.hal-dev and 20.hal-hotplug, hotplug, udev, and mingetty. Also, if I kill instances of those, more of them, or something else opens up, and if I try to kill those, something else pops open, and before I know it, instead of half a dozen processes running that shouldn't be, I've got five dozen running that shouldn't be.

Don't really know then. I would suggest disabling hotplug at boot and see what happens. My box (Slackware) was doing some strange stuff that stopped when I disabled hotplug.

interesting, i am still on 1pr, it works and i didn't see any more reasons to switch on 1.0, 1pr has been working wonderfully so far.

The only difference I know of is a cross scripting vulnerability
That under some circumstances could be a security problem .

I use Firefox 1.0 and it works just fine except that the close button has disappeared from the "find" bar, which is a nuisance because if you get tired of that wasted space you have to close and restart Firefox to get rid of it.

Speed is the same as with prior versions, which is to say VERY fast.

At the present time, and normally, Firefox runs four processes according to ps ax.

oh really, it shows up in mine, except in 1pr the close bottom is on the right corner, the 1.0 is on the left corner

Maybe I oughta reinstall my Firefox 1.0. It only takes a couple of minutes...

(Edited five minutes later) Reinstalled it, works OK, but still no close button for the find bar. What a waste of screen space. Guess I'll try to avoid finding things.

(Edited again after five more minutes and more rolling of eyes) It was the theme I was using, "Firefox Modern," which I INFINITELY prefer to the dorky default theme. With said dorky default theme I once again have my precious close button on the find bar. Not sure it's worth the visual tradeoff.

If I was a theme designer I'd be really...er...disturbed by having to re-craft my theme every time Firefox gets updated, which seems to be about once a week. I can see why a lot of very pretty themes have simply vanished.

Oh, well. Firefox is still the best we've got.

How do I do that? I'm still a bit new to Linux.

On my Fedora Core 3 (it did this also on Mandrake 10.1) A lot of the time whenever I open up Firefox, and I'm using the newest release, 1.0, the "Starting Mozilla Firefox" tab will display in the taskbar, and the boucing fox icon stays with my mouse. It will do that even after the browser comes up. I'm using the default theme.

Not familiar with FC. Slackware has a utility (pkgtool) that allows you
to do this, check your docs and see what utility FC has for this, or
man hotplug has instructions for enabling/ disabling

I don't use Slackware either, but did check my distro's man page and it appears that in Mandrake Linux you can start and stop hotplug like any other service. I. e. issuing as root, "/etc/rc.d/init.d/hotplug stop" to stop it, and so on.