[YLUG] Why is this so much faster on an Opteron?

[Richard G. Clegg]

Alex Howells wrote:
>> Nope.
>>
>> I have a Core 2 Duo laptop (gcc 4.1.2) running at 1Ghz and that takes
>> 32 seconds to run this. My office desktop is a Pentium D 3Ghz and it
>> takes 40 seconds :/
> 
> Both of which will be frequency scaled down quite considerably under a
> default installation of Ubuntu.

It will flip up to 100% "instantly" though (or it does on mine) -- test 
this with Ubuntu frequency scaling monitor.  For at least 15 of the 16 
seconds it takes on my laptop it is

gcc version 4.1.2

real    0m16.531s
user    0m16.321s
sys     0m0.052s

Laptop

vendor_id       : GenuineIntel
cpu family      : 6
model           : 15
model name      : Intel(R) Core(TM)2 CPU         T7200  @ 2.00GHz
stepping        : 6


time taken is more or less const if I use -O2 -O3 and -O4.

-- 
Richard G. Clegg,
Dept of Elec. Eng.,
University College London
http://www.richardclegg.org/