I couldn't figure out why suddenly after updating my nVidia drivers, I couldn't get BOINC to see both CUDA cards and process two CUDA work units.

I was reading elsewhere that starting with nVidia driver version 190.38 which has CUDA 2.3, the system will now only see 2 CUDA devices with SLI enabled, so you should now be able to enable SLI and leave it on all the time, even when running BOINC, just the opposite of the older drivers.

I checked my BOINC Manager, and sure enough, it was only showing one CUDA device. I exited BOINC, enabled SLI, and restarted BOINC, and then it showed two (I have two GTX 260's) and started processing two CUDA work units at the same time again.

So, just to make things more confusing for everyone, it appears that the rule for SLI flips for anyone who runs the newer 190.38 or higher drivers.

Anyone see something different?

this feature was in the release notes of driver 190.38.

your like the 5th person to realize this and post about it...

Yes, but in the other posts wasn't mentioned that now SLI must be enabled.

Gruß,
Gundolf

Yes, but in the other posts wasn't mentioned that now SLI must be enabled.

Gruß,
Gundolf

It's becoming apparent that this is only needed for some OSes - Vista x64 has been mentioned. I expect the 'Vista' bit is more important than the 'x64'.

I am indeed running a 64bit version of Vista. Perhaps people just need to see how things behave on whatever they run. Seems that at least on some systems, we don't have to turn SLI off anymore, and on mine, I MUST enable SLI for BOINC to even see more than one CUDA device, but I guess it's not true on all systems. I've seen posts in other forums this morning that indicate different people are seeing different results in relation to SLI settings, but at least if they can't see all the CUDA devices in BOINC, they now know something easy to try as a possible fix. Maybe in addition to the OS, the version of BOINC someone is running makes a difference on how it interacts with the new drivers. I'm running 6.6.38.