Just wanted to give everyone a head's up that Razer has just released new updates for both the Lachesis and the Deathadder gaming mices. Deathadder owners may now download the new v1.9 drivers while Lachesis owners, me included, will be offered to download both the new Lachesis Driver v1.10 and firmware 1.91. The latest firmware for Lachesis improves the tracking performance and response time of the mouse. Also, if you're among the little that still experience jump issues with Lachesis, this firmware will help you. I'm starting to update my Lachesis right now. Finally, all bugs that plagued Razer's Lachesis are now fixed.

Deathadder Drivers v1.09

http://www.razersupport.com/index.php?_m=downloads&_a=view&parentcategoryid=11&pcid=0&nav=0

Release Log:
- Fixed the bug where holding down a button on single key at advanced setting would act like a single keystroke. With this driver the key will repeat itself, just as when pressing and holding a key on a keyboard.
- Fixed Macro does not work if button was set to on-the-fly-sensitivity previously.

Lachesis Driver v1.10
http://www.razersupport.com/index.php?_m=downloads&_a=view&parentcategoryid=18&pcid=0&nav=0

Release Log:
- Fix single key implementation
- Fix save profile prompt box
- Fix mirroring issue of the side buttons.

Lachesis Firmware 1.91

http://www.razersupport.com/index.php?_m=downloads&_a=view&parentcategoryid=18&pcid=0&nav=0

Release Log:
- Improved tracking performance and faster response
- There are still a limited number of people with jump issues, this firmware addresses people with this issue.

Source: Razer