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

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Quote:
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.

Quote:
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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