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Old 2021-09-25, 08:28   #8
"Tucker Kao"
Jan 2020
Head Base M168202123

25·3·7 Posts

Originally Posted by Zhangrc View Post
The bounds are a little high, though.

Not that high. It's about 0.04/(2/78) = 1.56 times higher. However, with TF done to 2^78, one need smaller P-1 bounds to reach desired probability, thus saving more CPU time.
Taking M109999993 for example:
If it has been TFed to 2^76, then run P-1 with B1=700000 and B2=26000000, we get 65.9117% probability.
If it has been TFed to 2^77, then to get ~65.9117% probability, we only need to run B1=400000 and B2=10000000, getting 65.9167% probability and saving 7.4GHZdays per exponent.
Maybe most users have better GPUs than CPUs. It'll cost me more time to run TFs from 2^76 to 2^77 for M107M to M119M than the difference between the larger and the normal P-1 bounds on my PC.

However the GPU prices are skyrocketing recently, I'd rather to buy AMD Ryzen 5950X than Nvidia Geforce 3070 Ti if only 1 choice but not the other.

Originally Posted by Zhangrc View Post
Yes if you want to find more factors, no if you want to save more time.

You are referring to your 168,***,*23, I suppose?
TFs from 2^76 to 2^78 of M168M are around 46% faster to finish than 2^76 to 2^78 of M115M.
P-1 with B1 = 1,000,000 and B2 = 40,000,000 of M168M are 36% slower to complete than the same 2 bounds for M115M.

Last fiddled with by tuckerkao on 2021-09-25 at 08:36
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