[Openmcl-devel] 64 bit vs 32 bit

Waldek Hebisch hebisch at math.uni.wroc.pl
Fri Jun 12 11:06:35 UTC 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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