64 bits versus 32 bits Windows
 

Looking at benchmarks and the forum, am I right when I conclude that 64 bit Windows will only speed up trial factoring ? (And even then mostly for 1 to 63 bits factoring.) In other words would it be interesting to install Windows XP 64 or Windows Server 2003 64 on a machine dedicated to prime95?
I forgot one parameter: with a 64 bits windows you can install more memory, but once again this only favours factoring.

Another thing I am curious about : I saw in some well hidden place that an older version of prime95 (23.xx)was more efficient on PIII platforms than the current version (24,14). Is this still true?

Yeah 23.5 is about the best for the P3's. I have it on my work borgs.