Available straight from AMD's website
as well as various mirrors, the 64-bit version
of Unreal Tournament 2004 has been released, for those of us lucky enough to be using Athlon64s or EM64T processors. The update is available for free, but AMD's site requires registration to download it from them. There is a 64-bit client for both Windows and Linux, so whether you are using XP 64bit or x86-64 sources you can play. There are a few sites comparing 32bit server performance to 64bit server performance, and some synthetics, but real benchmarks aren't around yet so hopefully we'll soon see some results as to what the advantages of a 64bit client on a 64bit OS hold.