Hi,
I'm got a vista32 pc with 2 x gtx295's but cannot get boinc to recognise 4 CUDA devices. I've soldered up dummy video plugs, plus the desktop settings are aok and on 4 monitors, but at best boinc will recognise only 3 cuda devices.

If I turn Physx off it only recognises 2.

Sli is off in software. Drivers are 185.85.

Does anyone have any ideas?
Thanks,
Far

edit: Boinc 6.6.28

Did you turn on the flag to use all GPUs in the CC Config file?

There is an error that may cause one GPU to report slightly less memory, we think in the driver, and in the later versions of BOINC Dr. Anderson decided that this was sufficient to not use the GPU ... (I still don't know why, there is no explanation as to the rationale for the change) ...

{edit}

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

see Wiki

Still 3.

Did I do this correctly? On Vista I created a file called cc_config.xml in the C:\ProgramData\BOINC directory and put the text in from (edit) above.

The messages now have a note about being configured to use all coprocessors - but it only lists 3 CUDA devices.

Still 3.

Did I do this correctly? On Vista I created a file called cc_config.xml in the C:\ProgramData\BOINC directory and put the text in from (edit) above.

The messages now have a note about being configured to use all coprocessors - but it only lists 3 CUDA devices.

All 4 GPU's have the same driver. This machine is a clean (re)build. GPUz confirmed same bios in cards as well.

It seems to be mobo related. In the first slot both cards will run as 2 GPU's, but in the second slot they run as 1. Both slots are PCIe2.0x16.

Strange. Heard of anything like that before? It's an ASUS rampage Gene with the latest bios.

It seems to be mobo related. In the first slot both cards will run as 2 GPU's, but in the second slot they run as 1. Both slots are PCIe2.0x16.

I got problems with one 295 where only one cuda was recognised.
This seems to be a driver / Vista problem.
Running on XP Prof I got two cuda recognised withoud any problems.
If you get it working on Vista or Win 7 post it here.

Did you try using LimitVideoPresentSources in the registry?

This was the thing that finally got all 4 working for me (before the cc_config.xml flag was around).

If you need more info search back a couple of pages and you will see the full post.
____________

Do you diable the "Multi GPU Mode" for BOTH cards or only for one???

notice that both your GTX 260 cards are considerably faster than each core on the GTX 295

Are they? 260: 216 shaders at 1.24 GHz versus 295 with 240 shaders at 1.24 GHz ;)

Back from being out of town for a while..

Yes the 295 cores each run at roughly the same as the 295. Early on the 295 would rarely have completed a unit smoothly as I kept pulling the pc apart.

From reading around JockMacMad's theory looks like the most likely:

Did you try using LimitVideoPresentSources in the registry?

This was the thing that finally got all 4 working for me (before the cc_config.xml flag was around).

If you need more info search back a couple of pages and you will see the full post.

Having the same Problem trying to run 3 295's on a Gigabyte Extreme X58, it's nothing to do with BOINC as far as I can see right now anyway as the System itself reads differently each time I start it up. At best it reads 5 Cores but never the full 6.

One time it will see 5 Cores the next 4 then maybe only 3 depending how many of the 295's I put in and in which slots they are in.

PS: Does anybody know if I have to Install the Drivers for each 295 Installed, I ask this because when I put the Original 295 back in that it had & everything runs like it did. But with the New 295's in it's all screwed up, there not even a setting in the NVIDIA Control Panel for multi-GPU and PhysX ???

Checked all the registry stuff till I could understand it, ghosted the drive, then all psyched to regedit (I'm not that techy)...

But version 6.6.36 of boinc worked without having to touch anything!!

It's running 4 GPU's, all I've done is stuck the 3 dummy VGA loads on that I was using before to trick vista. Phew :-)

Having a simiiar problem with 1 GTX 295, BOINC only see's one of the GPU Cores but it shows 2 GPU Cores in the Device Manager: Using Client 6.6.36 Didn't work with v6.5 either & NVIDIS Driver v186.18 on Win XP Pro 64-Bit OS ...

6/24/2009 6:50:43 AM CUDA device: GeForce GTX 295 (driver version 18618, compute capability 1.3, 896MB, est. 106GFLOPS)

Yes it does allow SLi for gaming with the flag. It just tells the driver to advertise all the GPUs regardless of if there is a monitor plugged in or not.

By default Vista (and hence the nVidia driver) does not publish GPUs without monitors in non-SLi mode.

Using the registry forces the driver to behave much like XP did and always show all the GPUs.
____________

D'oh ... Thanks for Jogging my Memory Jock, I forgot you have to Disable Multi GPU Mode for the 295's to run both Core's, it's working now on both Cores ... :)