Existing users, 
Hey Swordman (and all),
Evidently installing 2.1 resets the speed modifier variable. But it's easy to adjust! Don't know why Logitech conceals it like this but once you know about it, it's right there. And it's been this way for some time now so give this a try: Just right click on the image of the mouse in the System Preference pane after you select the Logitech preference. This is BEFORE you click on the "Configure" button! You will see a Speed "Modifier" menu appear! Move over it and a hierarchal menu of speed modifiers will appear! Yours is probably reset to 1X with a checkmark next to it. Just select 2X or 4X and your mouse will be as zippier as ever! :)
Logitech Control Center
For their USB mice & keyboards.
Version: 3.1
Easy way to adjust Logitech mouse tracking speed!
Feedback Type: Usage Tip
Contributed by: ccrossman Friday, August 25 2006 @ 07:59 AM PDT
Product Platform: MacOSX
Used Product For: Over One Year
Comments
Easy way to adjust Logitech mouse tracking speed! - Weston Mason
Many thanks!Why did Logitech hide this??? They need some serious help with their interface design.
Happy Easter!
Friday, August 25 2006 @ 09:42 AM PDT
Easy way to adjust Logitech mouse tracking speed! - scaryfish
Note that you can use this in conjunction with the "Keyboard & Mouse" control panel - I had my mouse set on the maximum in keyboard & mouse, and 2x that is a bit too fast for me. I set the Logitech multiplier to 2x and lowered the speed a bit in the Keyboard & Mouse panel and now it's perfect.Sunday, August 27 2006 @ 06:23 PM PDT
Easy way to adjust Logitech mouse tracking speed! - 8paws4
Oh WOW! What a difference! Thanks for informing us/me as I did not know about the hidden function.Reply to This
Friday, August 25 2006 @ 09:31 AM PDT