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Old 2004-05-06, 10:42   #10
geoff's Avatar
Mar 2003
New Zealand

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Originally Posted by nuutti
How much faster GMP-ECM 5 is in p-1 factoring in the stage 2?

I am currently running P-1 for:

Can I use GMP-ECM 5 for runnig stage 2 in my test ?
(I have 2 Gbytes of memoy)
For a number this large Prime95 is faster. Gmp-ecm can test to higher bounds than Prime95, for 2^67108864-1 this is probably not a consideration, but I have done some timings on the smaller fermat numbers and I estimate that a P4 2.66GHz could test 2^262144-1 to B1=4290M in about 28 days with Prime95, or 2^524288-1 in about 60 days. From that point the fastest way to either extend stage 1 or start stage 2 is to use gmp-ecm separately on F18, F17, F16, etc.

According to, F18, F17, F16, F15 have only been tested to B1=32M, 64M, 250M, 1000M respectively.
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