20190819, 19:13  #1 
Oct 2008
n00bville
1325_{8} Posts 
highest testable LL exponent
Hi,
I have finished my 100M LL testing and so I am browsing through the map for a new challenge. https://www.mersenne.org/primenet/ The highest possible numbers are higher than 999000000 but in Prime95 Test it says it needs between 5 and 922600000. So what's the highest possible prime number I can savely test with Prime95 Windows executable? Is there a page to play around with possible values? Last fiddled with by joblack on 20190819 at 19:20 
20190819, 20:14  #2 
P90 years forever!
Aug 2002
Yeehaw, FL
1B65_{16} Posts 
AVX512 CPUs could go over 1 billion

20190819, 20:45  #3 
Oct 2008
n00bville
5^{2}×29 Posts 
Okay but Prime95 does say Prime95 Test it says it needs between 5 and 922600000 if I press 'Test'? I have a Ryzen 3700x with Windows 10. Last fiddled with by joblack on 20190819 at 21:02 
20190819, 21:14  #4  
Apr 2019
315_{8} Posts 
Quote:
(PARI/GP) Code:
? precprime(922600000) %1 = 922599973 

20190819, 21:46  #5 
Oct 2008
n00bville
5^{2}·29 Posts 

20190821, 10:01  #6 
Banned
"Luigi"
Aug 2002
Team Italia
2×3×13×61 Posts 

20190821, 14:40  #7 
P90 years forever!
Aug 2002
Yeehaw, FL
7,013 Posts 
From gwnum.h:
#define MAX_PRIME_AVX512 1169000000L /* AVX512 bit limit */ 
20191226, 15:25  #8 
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
7×601 Posts 
other software
Switching to CUDALucas, gpuowl, or Mlucas allows higher exponents, up to 2, 3 or 4 billion. But it is not advisable to run such extreme cases, because:
CUDALucas lacks certain error detection features necessary for such large/long runs; run times will be very long, likely longer than hardware lifetime; there is no established server to which to report the computation result of a primality test for an exponent above one billion, if one was reached. Last fiddled with by kriesel on 20191226 at 15:26 
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