[QUOTE=LaurV;323738]Checkpoint files include version number therefore different checksum. You may be able to trick the new version into believing the old checkpoints, if you modify the file (which is not difficult to do by hand). But generally assignments are very fast. Finish them with the old one, start new with the new one.[/QUOTE]

Ahh... clearly I've spoiled myself with CUDALucas. (Btw, there's an awesome surprise showing up on that front very soon.)

[QUOTE=ckdo;323690]Ain't gonna make me downgrade to a 32 bit distro.[/QUOTE]

You don't need to downgrade to a 32bit OS, you can run 32bit application in 64bit Windows/Linux...

It always appeared to me as if 32 bit apps in a 64 bit OS ran under some sort of compatibility layer, and somewhat slower than in the 32 bit version of the same OS, if they ran at all. This may have changed, however.

[QUOTE=ckdo;323751]It always appeared to me as if 32 bit apps in a 64 bit OS ran under some sort of compatibility layer, and somewhat slower than in the 32 bit version of the same OS, if they ran at all. This may have changed, however.[/QUOTE]I can't speak for *nix, but on Win64 I believe 32-bit apps can run just fine, albeit under [url=http://en.wikipedia.org/wiki/WoW64]WoW64[/url] -- the compatibility layer you speak of. It may "slow things down" very slightly, but in this case the benefits of the lower execution overhead of mfaktc32 vs mfaktc64 still show 32-bit as the winner for GPU-sieving.
16-bit apps, on the other hand, won't run on Win64 (they will on Win32). You can, however, usually run them inside DOSbox or similar (16-bit app in a 32-bit wrapper in a 64-bit wrapper).

In any case, on Win64 you can see from my post above that 32-bit mfaktc 0.20 is 1% faster than the 64-bit version (for the reasons Oliver explained above).

I have a suggestion for the documentation.

If the user switches to Stages=0 in the middle of an assignment that spans multiple bit ranges, then any work done in the current range will be lost. This should be noted in mfaktc.ini.

Every time I see that this thread has been posted in, I think "Yay, 0.20 is out of beta! GPU sieving for all!" and in all my excitement I accidentally the whole thing.

[QUOTE=c10ck3r;323831]Every time I see that this thread has been posted in, I think "Yay, 0.20 is out of beta! GPU sieving for all!" and in all my excitement I accidentally the whole thing.[/QUOTE]

Uhh what? You don't like betas? :confused:

[U][B]I[/B][/U] like BETAs just fine if they are made available. However, I have long had to cultivate patience when it comes to software/drivers/patches/updates, etc.

I do share c10ck3r's eagerness when I see a post in this thread, but these things happen when they happen.

[QUOTE=kracker;323833]Uhh what? You don't like betas? :confused:[/QUOTE]
Worst fish ever. They taste like plastic :razz:
No, I have no problem with beta testing, I just am looking forward to public release, hopefully w/o any errors.

mfaktc 0.20
 

Hello,

mfaktc 0.20 is finally available!
[LIST][*]Source code: [url]http://www.mersenneforum.org/mfaktc/mfaktc-0.20/mfaktc-0.20.tar.gz[/url][*]Windows executables (CUDA 4.2): [url]http://www.mersenneforum.org/mfaktc/mfaktc-0.20/mfaktc-0.20.win.cuda42.zip[/url][*]Windows executables (CUDA 4.2), [I]LessClasses[/I] for shortrunning jobs: [url]http://www.mersenneforum.org/mfaktc/mfaktc-0.20/mfaktc-0.20.win.cuda42.LessClasses.zip[/url][*]Linux executable (CUDA 4.2): [url]http://www.mersenneforum.org/mfaktc/mfaktc-0.20/mfaktc-0.20.linux64.cuda42.tar.gz[/url][/LIST]
Highlights:[LIST=1][*][B]GPU sieving[/B] for CC 2.0 or higher GPUs, [B]one[/B] instance per GPU, [B]very low[/B] CPU usage, recommended for all users when running on a supported GPU! Thank you very much George![*]three new kernels: barrett77, barrett87 and barret88. They are slower than barrett76 but faster than barrett79 so there is a performance boost for TF above 2[SUP]76[/SUP] and below 2[SUP]88[/SUP] compared to mfaktc 0.19. Again thank you very much George![/LIST]
There are some other changes, too, see the Changelog.txt for the full list.

As usual: finish your current assignment and upgrade to mfaktc 0.20 after that. The upgrade is recommended to everyone because a speed improvement is possible on all GPUs.


Happy factoring!
Oliver

Awesome! :banana: