I tried to install amd K7 kernel in ubuntu 11.10 (64 bit) but E: Unable to locate package
sudo apt-get install linux-k7 sudo apt-get install linux-k7-smp
Ubuntu does not provide processor specific kernels. If you are running a 64 bit version of Ubuntu then you are already running a kernel that will use the AMD K7 capabilities.
If you want a kernel compiled to match your specific processor then you will have to compile your own kernel. But it's almost certainly not worth your while - the link has reasons for and against if you want to know more.