SLI graphics card connector question.


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Questions and Answers : Windows : SLI graphics card connector question.

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musicplayer
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Message 1319151 - Posted: 23 Dec 2012, 3:12:33 UTC
Last modified: 23 Dec 2012, 4:08:18 UTC

I just connected my new PC to the web in my living room.

I was able to locate the hard disc I wanted to use after first using one which did not boot up. I will return back to that problem a little later on.

But yesterday I also ran this computer which now has two graphics card installed.

Then I was able to run two different CUDA-tasks at the same time. For some reason only one task is running at one time today, even though the other ones are "Ready to start".

I received an informational message about the advantage of connecting a SLI cable between the two graphics cards for better performance, but a quick look in the installation guide provides no information about this.

There is a possibilty that I may have more than one such SLI cable already, but if so, they may be of different types. The question is whether there are more than one connection or attachment point or place for each graphics card, which are Gainward GTX 680 cards, by the way.

Also, right now there are not too much software installed with these graphics cards. Only what is needed for running the Seti@home tasks as well as PrimeGrid tasks have been installed.

Edit on this: After receiving new CUDA-tasks for Seti@home, it became annoying that only one such task is running at a time right now. I will try turning off the machine and restarting a little later on.

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Message 1319186 - Posted: 23 Dec 2012, 6:44:43 UTC - in response to Message 1319151.
Last modified: 23 Dec 2012, 6:51:28 UTC

Shut down BOINC fully, open notepad, paste this into it WITHOUT the periods (...)

<cc_config>
...<options>
.......<use_all_gpus>1</use_all_gpus>
...</options>
</cc_config>

Save it as ccconfig.xml in BOINC/Program Data directory. After that open BOINC back up and both cards will be used.

If you end up saving it as a .txt file it wont work. you may need to rename it after and will have to change folder options in windows uncheck Hide extensions for known file types.
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Message 1319193 - Posted: 23 Dec 2012, 7:16:13 UTC - in response to Message 1319186.
Last modified: 23 Dec 2012, 7:56:32 UTC

I have done this right now. Still it does not work.

Perhaps the graphics card died or does not work right now. Still I am only getting one task to run at time, possibly there was a speed increase - not sure right now.

Why did it work yesterday? I am not having a connection between the two cards by means of SLI yet as already mentioned, but this should not be the whole reason for this error.

Edit: After a restart of the computer, I think that both graphics cards are working. So it is a configuration problem.

Perhaps I should try reverting back to the original configuration and try again. I did so and restarted BOINC Manager.
With CUDA disabled in Preferences, I try enabling my CUDA tasks one by one after first suspending all of them.

Interestingly, the three first tasks are "Waiting to Run" and the next four tasks are "Ready to Start" - apparently using the original settings. And it still runs only one task when I re-enable CUDA. Restoring the file with the suggested configuration apparently gives me the same result as using the original settings.

Why is it so?

Oops! Still musicplayer, by the way. Sorry about that!

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Message 1319203 - Posted: 23 Dec 2012, 8:31:00 UTC
Last modified: 23 Dec 2012, 8:39:45 UTC

I have re-started the computer after applying a Windows Update.

According to Control Panel, one of the graphics cards had a configuration error.

This has now been solved. Perhaps this was the reason for the status messages I received when trying to restart tasks from suspended With or without CUDA enabled.

Anyway, with both cards now working, I am still only able to run one CUDA-task at a time.

I have tried both using the original configuration and the suggestion here without any good luck.

In fact, I used the Windows Task Manager and killed off all BOINC tasks, which should make it clear there was nothing left out.

Any other suggestions to a solution to this problem?

I give up for now and have a break. Remember, Christmas is coming up.

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Message 1319222 - Posted: 23 Dec 2012, 11:07:11 UTC - in response to Message 1319203.
Last modified: 23 Dec 2012, 11:14:00 UTC

I am so sorry

The file name needs to be cc_config.xml

I made type-o when I posted that and didn't notice, I am so sorry you went through all that. My mistake, do as I mentioned before and you will have solved it.

Just save as cc_config.xml and save in ProgramData/BOINC directory

It works please believe me, I have had to do it two times before. I dont know where your folder may be as I have custom directories on my side. But it needs to be in where ever your Boinc folder is under ProgramData/BOINC
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phO·kaz [foh-kuh s]
noun, plural fo·cus·es, fo·ci , verb, fo·cused, fo·cus·ing or fo·cussed, fo·cus·sing.

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Message 1319255 - Posted: 23 Dec 2012, 13:31:57 UTC

BOINC uses only the best GPU that it detects, and it determines which is best on the following factors, in decreasing priority:
1 - compute capability
2 - software version
3 - available memory
4 - speed

You may have two GTX 680s there, but the first is probably being detected as having 8381200MB of memory, whereas the second only has 4096MB. So the first one is definitely superior. ;-)

You've been bitten by the memory detection bug that's in a lot of BOINC versions, including in 7.0.28. The first reliably working fix for this bug is in 7.0.36 or .38 (I forget which). So if you don't mind running a beta BOINC, you can upgrade to the latest stable testing version, 7.0.40. A change log for it and download links to it can be found in post 46649 of the BOINC 7 Change Log Thread.

Or you can upgrade to 7.0.42, which amongst things includes the first rendition of Intel HD Graphics 2500/4000 GPU OpenCL support, while it also includes the use of the new application configuration file (app_config.xml), with which you can tell BOINC how many instances of tasks to run on CPU and GPU, without needing to use the anonymous platform (app_info.xml).

See post 46743 in that same thread for download links and the change log.
See ClientAppConfig for information on how to use the app_config.xml file.
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Message 1319734 - Posted: 24 Dec 2012, 22:49:49 UTC
Last modified: 24 Dec 2012, 22:51:36 UTC

Good news for you tonight.

The problem has been solved and once more, both graphics cards are now running CUDA-tasks at the same time.

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Message 1319756 - Posted: 25 Dec 2012, 0:32:40 UTC
Last modified: 25 Dec 2012, 0:39:47 UTC

Perhaps not completely solved yet.

I notice that while I get both CUDA-tasks running now, only 11 CPU-tasks are running - not 12, as it should be. It runs 12 CPU-tasks if only 1 CUDA-task is running. If both CUDA-tasks are active, that CPU-task is "Waiting to Run".

Is this because of the lack of the SLI-cable which has not been connected yet?

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Message 1321930 - Posted: 30 Dec 2012, 3:44:17 UTC
Last modified: 30 Dec 2012, 3:46:56 UTC

Right now I am on Windows 8, 64 bit once again.

BOINC Manager 7.0.28(x64).

I have two Seti@home CUDA tasks running at the same time.

But here only 11 tasks are running by means of the CPU. The twelfth task is "Waiting to run". Possibly this problem was not there when trying out the same using Windows 8, 32 bits, but I will have to go back and check.

In Preferences, Run time settings (oh, my native language in the menus, but at the bottom there), the program was set up with the "On multiprocessor systems", use at most 0,00% of the processors.

I tried changing that to 100,00% instead since I know this has been working earlier, but this did not help. What more is needed? I also tried re-Reading the local configuration file and local preferences file. The two CUDA-tasks are left running.

Next option is exiting BOINC Manager completely and restarting it.

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Message 1325800 - Posted: 8 Jan 2013, 14:47:10 UTC - in response to Message 1319734.

Good to hear :-D
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Message 1326413 - Posted: 10 Jan 2013, 17:59:58 UTC

What is probably happening is that each GPU task is allocated a little bit of a CPU (the GPUs need to be fed data from the CPU). When you have two GPU tasks running, this uses enough of a CPU to make BOINC decide to halt another CPU task altogether so that the GPU tasks may run properly.
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Questions and Answers : Windows : SLI graphics card connector question.

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