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Old 2018-07-18, 13:16   #7
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Sep 2003

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Originally Posted by ATH View Post
It does not *need* 120GB, because I did a few curves a while back and I only have 32 GB RAM. It took ~95 hours with all 8 cores on Haswell-E assigned to it, but I am not sure how much effect many cores have on ECM tests.
I am using a single core, and stage 2 takes about 40 hours and uses 95% of the memory. No doubt it could use less memory at the expense of taking extra time. Stage 1 takes about five days.

The machine is an r4.4xlarge on AWS, with eight cores. The "R" instance types have much more memory than the "C" types but slower processors. I'm using the other seven cores to do ECM on small Mersenne numbers because I worried that the Fermat ECM wouldn't use all eight cores cost-effectively. I didn't actually try it though, maybe I will.
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