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garo 2011-10-15 10:54

GPU Trial Factoring FAQ
Please post additional questions/answers below. I'll update the FAQ on a regular basis.

Q. Can I use my GPU to trial factor Mersenne numbers?
A. If it is a relatively modern GPU, yes. You can see the list of Nvidia supported GPUs here: [URL][/URL]

Q. So what software do I use and where do I get it?
A. For nvidia based GPUs use mfaktc [URL][/URL] .
For other GPUs use mfakto an OpenCL implementation. The latest version is here: [URL][/URL]

Q. How do I get work?
A. At the time, mfaktc cannot get work from Primenet automatically. You need to get assignments from the manual assignments page and turn the results in likewise.

Q. Where do I put those assignments?
A. In the worktodo.txt file.

Q. Do I need to stop mfaktc to add more to the worktodo.txt file?
A. No. As long as you don't mess with the first line and take care not to save your hand-modified worktodo.txt while mfaktc is modifying it (after having finished a test or found a factor).

Q. Will the completed work automatically be removed from the worktodo file?
A. Yes.

Q. Where are the results stored?
A. In results.txt.

Q. Does mfaktc require CPU time?
A. Yes. The sieving part of the trial factoring process is done on the CPU. If you have a fast GPU e.g. GTX 460 or above, you may need to run multiple instances of mfaktc - each using one CPU core - to get the most out of your GPU.

Q. Why do I get a missing dll error?
A. Get them here: [URL][/URL]

Q. Is there a wiki with more info?
A. [URL][/URL]

Brain's quick start guide is attached to this post. It is a handy one pager with all the critical information.

PDF Guide:
[URL=""]GIMPS GPU Computing Cheat Sheet (pdf)[/URL]

kladner 2011-10-15 15:06

Many thanks for getting this started, garo! I am sure it will save many beginners (like me) a lot of thrashing about.

Brain 2011-10-15 16:11

GPU Computing Guide Update to v 0.05
Latest version...

[URL=""]GIMPS GPU Computing Cheat Sheet (pdf)[/URL]

kladner 2011-10-15 16:17

Wow! Great update, Brain! Thanks!

ixfd64 2011-10-15 17:49

Q: When will we have a version of Prime95 with GPU support?
A: When it's doneā„¢. :smile:

Dubslow 2011-10-15 23:16


Dubslow 2011-10-15 23:25

[QUOTE=Brain;274629]Latest version...[/QUOTE]

Hmmm.... I can't click on the links, and version 3 still works fine in the same program.

Dubslow 2011-10-15 23:31

Q. Can I use my GPU for LL testing?
A. Yes, with the program called CUDALucas, with NVidia supported GPUs.

Q. Where can I get the software?
A. See the attached PDF guide.

Q. How do I get work for CUDALucas?
A. You will need to get manually get work from PrimeNet like mfaktc, however CUDALucas currently doesn't use a worktodo file. You test an exponent by using a command line argument; or, to test multiple exponents, use a batch file. (Garo: kladner has a couple of batch posts in the GPU-Noob thread.)

Q. Where are the results stored?
A. mersarch.txt

kladner 2011-10-16 01:52

"I can't click on the links"

Yikes! I didn't check, but it's true. The layout looks good.

Christenson 2011-10-16 02:34

I thought the trhead below might have been the right one to make sticky....
[url][/url] ("Putting it All Together")

Kindly someone look through there and patch up any holes in this thread....

And Garo, is this thread limited to mfaktc, or do we also cover CUDALucas, in which case the title is a bit "off"?


kladner 2011-10-16 03:32

[QUOTE] this thread limited to mfaktc, or do we also cover CUDALucas.....[/QUOTE]

Might it not be better to keep threads on different programs separate to do some of the sorting up front? I thought about "GIMPS GPU FAQ", but then we'd immediately need sub-threads for mfaktc, cudalucas, [other current GPU programs], and [future GPU programs which will appear].

Which is better? Individual FAQs for different programs, different languages, different GPUs? Or sub-threads to an over-arching FAQ?

I don't know. Just asking. I'm sure there are other organizations possible, or already existing. But I think it is worth examining how to keep the structure as intuitive as possible if it is aimed especially at beginners.

As one such, I've trolled through many threads, reading comments and grabbing downloads of advancing program versions; some of which contained contained code for compilation and/or compiled exe's for 32 and 64 bit [I]Windows[/I] versions. So far, for me, compiled binaries, along with links to necessary dll's have been vital resources. Of course, README's, explanatory comments in ini's, and [program name].txt files are invaluable.

OUCH. I just stepped into another cow pie. I'm only running Win XP-32 and 7-64 right now. I have messed with Red Hat Linux in the past, even to the point of modifying and compiling kernel code for a specific CPU etc. But I have no grasp of GIMPS in the Linux domain today except to know that there are Linux versions available or possible for some flavors of Linux.

In any case, that adds another category to the organization tree. Clearly, I'm only bloviating, as I am not in a position to set up structures. But I think, in the interest of getting newcomers hooked up and productive, that it's worth thinking about how to make basic things available and minimally understandable for well intentioned ignoramuses.

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