I have tried to get a measure for the performance ratio between 64- and 32-bit code, but the forum I posted to was inhabited by denizens who apparently had such clunkers that they couldn't run the benchmark. All it requires is a machine running 64-bit windows. There are 10 benchmarks, 2 32-bit ones and 8 64-bit ones. All of them are brief, only a couple of seconds on a fast machine. Of the 64-bit banchmarks it's only necessary to run the KMB_V0.57_2T_X?.exe ones if your machine has no more than 2 cores counting hyperthreading or KMB_V0.57_MT_X?.exe if you have more than 2 cores.
Useful results look like this:
processor: core 2 duo e6700
speed: 2.66 GHz
sockets * cores * hyperthreads: 1*2*1
KMB_V0.53_MT_FPU.exe: 336.321 million iterations/sec
KMB_V0.53_MT_SSE2.exe:736.472 million iterations/sec
KMB_V0.57_2T_X1.exe:817.711 million iterations/sec
KMB_V0.57_2T_X2.exe:1207.928 million iterations/sec
KMB_V0.57_2T_X3.exe:1678.401 million iterations/sec
KMB_V0.57_2T_X4.exe:1967.415 million iterations/sec
KMB_V0.57_MT_X1.exe:807.112 million iterations/sec
KMB_V0.57_MT_X2.exe:1186.070 million iterations/sec
KMB_V0.57_MT_X3.exe:1645.114 million iterations/sec
KMB_V0.57_MT_X4.exe:1910.082 million iterations/sec
There is already a table available for the 32-bit form of the benchmark, but I think that some of the users of this forum have much better machines and I hope to see better results, especially with the 64-bit code!