After the upgrade to 12.04, it doesn't find drivers for my Radeon 2100 in the "Additional Drivers" window. I can't remember having problems with this before. Moving windows etc is very slow, and I suspect this is because of the missing driver.
Is there an easy way to install the driver for Radeon 2100 on Ubuntu 12.04?
$ lspci -nn | grep VGA
01:05.0 VGA compatible controller [0300]: Advanced Micro Devices [AMD] nee ATI Radeon 2100 [1002:796e]