How can I enter a larger exponent?

[retina]

Originally Posted by ewmayer

That's a more-or-less "budget system" - perhaps ~20 years on the kind of systems I'm using for F30.

I wish my old Banias system had more RAM. I want to beat my current record of 37.5 years.

[ewmayer]

Originally Posted by retina

I wish my old Banias system had more RAM. I want to beat my current record of 37.5 years.

That's a 100Mdigit number - my timings are for a 1Gdigit one. Or do you mean 'beating' in the sense of yielding an even more-ridiculously-long runtime?

[retina]

Originally Posted by ewmayer

That's a 100Mdigit number - my timings are for a 1Gdigit one. Or do you mean 'beating' in the sense of yielding an even more-ridiculously-long runtime?

Bigger numbers are always better, or course. I still hold the record, no one has beaten my time.

[LaurV]

Originally Posted by evanh

is this the Titan you are referring to? https://www.olcf.ornl.gov/titan/

Haha, no, it is not that one, we totally wish to have access to such an alien monster, but our pockets are not so deep, and our job in on the other side of the world...
(we are still trying hard to determine if you are serious, or making fun of us, i.e. trolling)

This is the titan every body is talking about, on these particular math-related forums. Actually, not exactly that, but the one before it, without the "black" particle, but it seems to be phased out completely by NV, no links there. Note that this is quite an "old" card already, some new "gaming" cards can beat its performance per_watt, or even per_wall_clock_and_watt, but they are not so common (yet) in the prime-hunter's systems. On this page you can see some benchmarks, which you can translate in working days/weeks/months/years with a simple formula depending on your exponent. Or, if you are lazy to use the formula, you click here and see you need about 92k GHzDays to do a 1G test, which divided by 80 (about the daily harvest of the Titan), you get about 3 years and a half. Again, this is quite optimistic. The big problem with this is that you will need two Titans in parallel to run the DC (double check) with a different shift, because the Titan does not have ECC memory, and one FFT error in the beginning of the test may render all the test useless, and just waste all the power and effort for the 3-4 years.

My (slightly overclocked) Titans have the bad habit to spit out a mismatch (I always run two in parallel) every 50-80-100 million iterations or so, for an 100M exponent. I assume that for 1G exponent (if you would have the right program, as CudaLucas can not go so high yet) you may have an error every 10? 20? million iterations...

But with a Tesla (say the top Pascal, harvesting about 200GHzDays per day), with ECC memory and all stuff, you may do your 1G test (again, if you have the program) in about 480 days, or an year and half.

Again, this calculus is very optimistic, and a lot of assumptions are wrong, like for example I assume that the test will go well and uninterrupted, day and night, and I also assume that the output performance of the card does not degrade with the growing of the FFT (which is false) - this paragraph added to avoid Retina coming here and taking me apart piece by piece, hehe...

etc...

[axn]

Originally Posted by LaurV

This is the titan every body is talking about, on these particular math-related forums.

https://www.nvidia.com/en-us/titan/titan-v/ is the new king.

Originally Posted by LaurV

Or, if you are lazy to use the formula, you click here and see you need about 92k GHzDays to do a 1G test, which divided by 80 (about the daily harvest of the Titan), you get about 3 years and a half.

That calculator is wildly wrong. It will take about 0.5-1m GHz days to do a billion digit test.

Originally Posted by LaurV

The big problem with this is that you will need two Titans in parallel to run the DC (double check) with a different shift, because the Titan does not have ECC memory, and one FFT error in the beginning of the test may render all the test useless, and just waste all the power and effort for the 3-4 years.

Definitely need to use Gerbicz PRP check for these tests.