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20211021, 13:50  #1 
Oct 2021
U.S. / Maine
144_{8} Posts 
Prime95 defaults to proof=8 for PRPCF tests even though I have a very large disk space allocated
I have my Prime95 in a dumb directory that I don't use much and so gave it 100GB for proofs. Wavefront PRP selects proof=10, as expected. But — I recently started running PRPCF instead out of interest and every test selects proof=8.
I understand that this is almost completely inconsequential because even a power7 proof on a cofactorsize number would take trivial time to certify. But — I have to say I'm still curious why the program does not select a higher proof power for this specific type of test, when the space for one is certainly available. I searched for "PRP cofactor proof power" but could only find unrelated posts. 
20211021, 14:13  #2 
Jan 2021
California
253_{10} Posts 
It's probably related to the size of exponent you are now getting, there's really no reason to generate a giant proof file, and I wouldn't worry about it. Those certs take seconds to run (minutes on older slow hardware).
Last fiddled with by slandrum on 20211021 at 14:14 
20211021, 14:16  #3 
Jan 2021
California
11×23 Posts 
If you are really concerned and want to force a particular proof level, read undoc.txt and it will tell you what line to add to local.txt
Last fiddled with by slandrum on 20211021 at 14:16 
20211021, 14:18  #4 
Oct 2021
U.S. / Maine
2^{2}·5^{2} Posts 
I figured there would be something in undoc. I'll take a look.

20211021, 14:42  #5 
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
13445_{8} Posts 
Please read and apply https://www.mersenneforum.org/showpo...64&postcount=2
Specifically, "Use an existing topicspecific thread when practical." There are multiple existing prime95 threads, version dependent. A moderator may choose to merge this newly created thread into an existing thread. Please do not make extra work for the moderators. Also, read the fine manual files; think; apply; before posting. Last fiddled with by kriesel on 20211021 at 14:45 
20211021, 17:28  #6  
Oct 2021
U.S. / Maine
2^{2}·5^{2} Posts 
Quote:
So, you're saying it would have been appropriate to post this in the "Prime95 v30.4/30.5/30.6" (I'm running 30.6b4) thread? If so, apologies; I was under the impression that the versionspecific threads were strictly for testing and debugging of new features in the relevant versions and it would be incorrect to clutter them up with procedural questions. Quote:
Of course. At the end of the day I'm only secondarily concerned with the ability to run proof=10 PRPCF; I was more curious if there was any reason why the program doesn't select proof=10 for PRPCF when the disk space is available, beyond the obvious "the certs are quick anyway so it's a nonconcern." But I suppose not. 

20211021, 22:37  #7 
P90 years forever!
Aug 2002
Yeehaw, FL
7688_{10} Posts 
Running proof=10 on small exponents will cost more generating the proof than you will save doing the cert.

20211022, 00:00  #8  
Oct 2021
U.S. / Maine
2^{2}·5^{2} Posts 
Quote:
Thank you for the insight! Approximately where are the cutoff points at which the optimal power goes up? Would Prime95 set proof=11 or proof=12 for a sufficiently large exponent (say, 100Mdigit) if the disk space was allocated? 

20211022, 03:13  #9 
P90 years forever!
Aug 2002
Yeehaw, FL
2^{3}×31^{2} Posts 
Over 414.2M the proof power goes to 11.

20211022, 03:44  #10 
Oct 2021
U.S. / Maine
1100100_{2} Posts 
OK, so it scales very slowly. Interesting. I happen to do DCviaPRP using GPUOwl, which of course doesn't get more nuanced than using one, preset proof level for every test. I didn't have the information from this thread when I was tuning my installation and set proof=10 without thinking about it. At the current DC wavefront, would it actually be more efficient to use proof=9? If yes, around what exponent should I go back to 10? Thanks again for your insights thus far 
20211022, 05:32  #11 
P90 years forever!
Aug 2002
Yeehaw, FL
1E08_{16} Posts 
1.7M  6.7M = 7
6.7M  26.6M = 8 26.6M  106.5M = 9 106.5M  414.2M = 10 414.2M+ = 11 
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