Ubuntu 7.10 (Gutsy Gibon) Final - 64-bit PC (AMD64) desktop CD
The desktop CD allows you to try Ubuntu without changing your computer at all, and at your option to install it permanently later. This type of CD is what most people will want to use. You will need at least 320MB of RAM to install from this CD.
64-bit PC (AMD64) desktop CD
Choose this to take full advantage of computers based on the AMD64 or EM64T architecture (e.g., Athlon64, Opteron, EM64T Xeon). 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.