Are 64-bit Binaries Slower than 32-bit Binaries?

JigSaw writes "The modern dogma is that 32-bit applications are faster, and that 64-bit imposes a performance penalty. Tony Bourke decided to run a few of tests on his SPARC to see if indeed 64-bit binaries ran slower than 32-bit binaries, and what the actual performance disparity would ultimately be."