Mac OSX, GPU/CUDA Usage

[David C Mackay]

I have tried going via FAQs for help here but got swamped by Windows solutions. Can anyone tell me whether or not I can boost my Prime95 efforts by exploiting the NVIDIA GeForce GT750M card on my MacBook Pro? I do have some CUDA bits and pieces installed to support an application called Mathematica.

[Prime95]

You cannot speed up prime95 with the GPU.

You could run mfaktc to do trial factoring, but I believe that will cause prime95 to slow down as the OS clocks the CPU down to keep power usage under the Apple-approved value.

[David C Mackay]

Many thanks for the prompt response. I shall just let the CPU cores do their best.

[Prime95]

Did you look in the preferences dialog box. There is an OS X specific option you can set.

[xilman]

Originally Posted by Prime95

You cannot speed up prime95 with the GPU.

True.

You can, however, use the GPU to speed up other factoring work. In the past I've successfully used my MacBook with GMP-ECM and polynomial finding with msieve.

If you're interested in non-Mersenne work a number of people will willingly help you.


Paul

[bayanne]

I was running mfaktc on my MacPro for awhile, and then changed to an iMac, and have started running it again.
I obtained a compiled copy of mfaktc from another contributer, who I don't think is crunching Prime95 at the moment.
It of course only does trail-factoring ...

[bayanne]

I am running it with NVIDIA Web Driver: 346.03.06f01 with MAC OSX El Capitan

[bayanne]

I have been trying to get mfaktc-0.21 compiled but without success. I have CUDA 7.5 downloaded, but when I run gcc mfaktc.c it cannot find cuda.h which I know is in the CUDA 7.5 directory.

Can anyone with compiling skills on a Mac help me out?

[xilman]

Originally Posted by bayanne

I have been trying to get mfaktc-0.21 compiled but without success. I have CUDA 7.5 downloaded, but when I run gcc mfaktc.c it cannot find cuda.h which I know is in the CUDA 7.5 directory.

Can anyone with compiling skills on a Mac help me out?

I need to fire up the Mac and see how the latest Xcode works first. Not used CUDA for Mac in a few years. Guess is that a -I somewhere should do it. If all fails, try #include "/explicit/path/to/cuda.h" change to the src.

[bayanne]

I have used the following:

export PATH=/Developer/NVIDIA/CUDA-7.5/bin:$PATH
export DYLD_LIBRARY_PATH=/Developer/NVIDIA/CUDA-7.5/lib:$DYLD_LIBRARY_PATH

This works fine with mfaktc-0.20 and specifying CUDA-5.5, but the file cuda.h (if that is what I should be referencing) is in /Developer/NVIDIA/CUDA-7.5/include rather than /bin

What is actually being said in that export statement and what should I be saying to compile mfaktc - hopefully

[diep]

Originally Posted by David C Mackay

I have tried going via FAQs for help here but got swamped by Windows solutions. Can anyone tell me whether or not I can boost my Prime95 efforts by exploiting the NVIDIA GeForce GT750M card on my MacBook Pro? I do have some CUDA bits and pieces installed to support an application called Mathematica.

hi David!

the macbookpro (17'') here basically overheats if it's eating more than 50 watt roughly. It's simply melting things underneath it. That happens when the cpu cores are at full load and the gpu isn't yet.

The GPU under full load will add another 40 watt to that so it's crucial to keep the CPU cores idle while running the CUDA cores at full throttle otherwise you'll melt a hole in the table.

I tried additional cooling here for the macbookpro, as the 2 delta fans even at full throttle making stupid high noise, can't remove enough watts. Underneath it i put copper heatsinks against the hot bottom of the laptop and active cooling. That removes a little yet not enough.

As a result, i do not crunch on the laptop.

p.s. the maximum i could achieve with that additional cooling on the bottom of the laptop was with 1 core busy running HD video. So the GPU must've eaten a watt or 25-30 or so then. Temperature then would be nearby 90C.

The lithium ion battery would be removed in such occasion - as even despite that i'm busy with my 4th laptop battery.