[Openmcl-devel] 64 bit vs 32 bit

Waldek Hebisch hebisch at math.uni.wroc.pl
Fri Jun 12 04:06:35 PDT 2009

Neil Baylis wrote:
> Is there any advantage to using the 64 bit version on a system with less
> than 4 GByte of memory? Is it superior to the 32 bit version in any other
> ways?

64 bit version has bigger fixnums.  For me it means that 64 bit
version freqently is able to do computations using fixnums,
while 32 bit version has to use bignums.  I did not try 32 bit
Closure CL, but for sbcl it happend few times that 32 bit version
was about 10 times slower than 64-bit one.  In principle 64
bit version should have faster bignums, but IIUC in Closure
CL 32 and 64 bit versions use essentially the same code for
bignum arithmetic.

                              Waldek Hebisch
hebisch at math.uni.wroc.pl 

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