AMD 64-bit performance tested
AnandTech has put together a set of tests
using an Athlon 64 with both 32-bit and 64-bit versions of Windows, SuSE Linux, and Red Hat (Fedora) Linux. They've measured performance in media encoding, gaming, rendering, and database applications. Although 64-bit binaries weren't available for many of the Windows apps, some of the full-on 64-bit benchmarks show marked performance jumps over 32 bits. Looks like the extra registers in the AMD64 architecture promise some very nice speed increases once the right software becomes more widely available.