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Old 2020-10-13, 02:10   #16
kriesel
 
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"TF79LL86GIMPS96gpu17"
Mar 2017
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Quote:
Originally Posted by clowns789 View Post
Interestingly, according to the following link, factoring to 91 bits would require over 150K GHz-days of computation, while a LL test requires only 91K:
Not all GhzD are equal.
Historically, TF was done on cpus, as was LL, and at that time there was no GIMPS PRP. The GhzD unit of measure was set as one core of a theoretical 1Ghz Core 2 processor.
Gpus have much faster single precision or integer speed (relevant to TF) than DP (relevant to P-1, LL, and PRP); in some cases as much as 8x, 12x, 16x, or more (although some rare models are 2x or 3x). In cpus the ratios I've seen ranged from 0.7 to 1.4.
On a gpu, a TF GhzD occurs much more quickly than a P-1 or PRP or LL GhzD.
Compare GhzD/day figures for TF https://www.mersenne.ca/mfaktc.php and for LL / PRP https://www.mersenne.ca/cudalucas.php for the same gpu model.
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