Kubuntu 11.10 Amd64 CD is suitable for most computers. The combined install/live DVD allows you either to install Kubuntu permanently on a computer, or (by entering 'live' at the boot prompt) to try Kubuntu without changing your computer at all. Choose this to take full advantage of computers based on the AMD64 or EM64T architecture (e.g., Athlon64, Opteron, EM64T Xeon, Core 2). If you have a non-64-bit processor made by AMD, or if you need full support for 32-bit code, use the Intel x86 images instead.
Kubuntu is a free, user-friendly Linux distribution based on KDE's desktop software and on the award-winning Ubuntu operating system. It has a biannual release cycle and at least 18 months of free security updates for each release. Besides providing an up-to-date version of the KDE desktop at the time of the release, the project also releases updated KDE packages throughout the lifetime of each release.