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Old 2009-03-03, 10:30   #1
MatWur-S530113
 
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Default curious timings running ECM curves

Hello,

atm my computer run ECM curves with B1=11e6 at M2539 and M2543.
For M2539 prime95 uses FFT 112. One curve needs ~225 sec for stage 1 and ~76 sec for stage 2.
For M2543 prime95 uses FFT 128. One curve needs ~183 sec for stage 1 and ~72 sec for stage 2.

Is it possible to run prime95 with the larger FFT size at the smaller M2539, too? I could save ~40 sec per curve, and I want to run 2000 curves or so.

Matthias
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Old 2009-03-03, 14:45   #2
Prime95
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You can force the larger FFT size. After the long assignment ID (or the string "N/A") in worktodo.txt insert the text ",FFT2=128" assuming this is an SSE2 machine. Use ",FFT=128" for non-SSE2 machines.
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Old 2009-03-03, 18:44   #3
MatWur-S530113
 
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Thank you, this works fine. Indeed the curves about 40 sec faster now.

best regards,

Matthias
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