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[cmdrdredd]

Are you overclocking and have them set to sync the clocks? Other than that which I'm not even sure...I dunno. Honestly I never looked to see what the cards were clocked at when running single. Guess I'll have to check that.

 

[bystander36]

For some reason, and maybe it is a bug with the current driver version I'm using, but "Single-GPU" mode is not working like it is supposed to. It is not disabling SLI for me to test. I'm using drivers 320.14. If I disable SLI from the SLI menu, then only one cards clocks increase, but the per profile, or even 3D settings option does not work with the drivers I'm using to even test.

As far as the VRAM goes, having access to the 2nd card's VRAM does not help the 1st card in any way other than possible GPU accelerated PhysX. The 1st card can only use the 1st cards VRAM.

 

[cmdrdredd]

I'm running 320.14 and just checked this. Setting single gpu mode and watching the OSD, only the first card is boosting. The second one is at default.

edit: it isn't running at "idle" clocks (325Mhz). It's running the default 3D clocks of 1006 or whatever.

 

[bystander36]

I'm running 320.14 and just checked this. Setting single gpu mode and watching the OSD, only the first card is boosting. The second one is at default.

edit: it isn't running at "idle" clocks (325Mhz). It's running the default 3D clocks of 1006 or whatever.

I wasn't paying attention to what boost was used, but both my cards are showing a good load %, and performance is like it normally is in Skyrim, the one I tested, when normally when SLI is disabled, I get horrible frames.

I am pretty sure it has worked in the past, but right now, SLI is not being disabled with the drivers I'm using.

 

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[Carfax83]

Perhaps it's a driver bug.. At any rate, the sure fire way to disable SLI is to remove the SLI bridge.

 

[bystander36]

I do notice that MSI afterburner and EVGA Precision X, even at the desktop, will show the vram the same at all times. I know at the desktop the 2nd video card is not doing anything, so I'll chalk this up to the monitoring software.

 

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[ViRGE]

"Single-GPU" mode in a profile isn't the same as disabling SLI. So long as SLI has been activated in the NVIDIA control panel, then SLI is always active regardless of the specific game profile in use. The only thing the single-GPU setting in profiles controls is whether the second GPU receives any work.

This is because NVIDIA can't actually fully disable SLI on the fly like that. When SLI is enabled/disabled, the drivers have to present a bunch of information to Windows, let Windows change the configuration (between linked mode and secondary mode), and then reinitialize the GPUs. Which is why it takes several seconds and your screen will flash during the process. Consequently the single-GPU setting in a profile doesn't turn off linked adapter mode (SLI) but rather doesn't send the linked GPUs any work. You're technically still beholden to SLI power and memory management. This is also why some games have worse performance in SLI single-GPU mode than having SLI properly disabled, as games that detect linked adapters (to decide whether they need to follow a more AFR-friendly code path) will still think that they will be feeding multiple GPUs.

 

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[bystander36]

"Single-GPU" mode in a profile isn't the same as disabling SLI. So long as SLI has been activated in the NVIDIA control panel, then SLI is always active regardless of the specific game profile in use. The only thing the single-GPU setting in profiles controls is whether the second GPU receives any work.

This is because NVIDIA can't actually fully disable SLI on the fly like that. When SLI is enabled/disabled, the drivers have to present a bunch of information to Windows, let Windows change the configuration (between linked mode and secondary mode), and then reinitialize the GPUs. Which is why it takes several seconds and your screen will flash during the process. Consequently the single-GPU setting in a profile doesn't turn off linked adapter mode (SLI) but rather doesn't send the linked GPUs any work. You're technically still beholden to SLI power and memory management. This is also why some games have worse performance in SLI single-GPU mode than having SLI properly disabled, as games that detect linked adapters (to decide whether they need to follow a more AFR-friendly code path) will still think that they will be feeding multiple GPUs.

Like I said above, when I set Single-GPU mode, both cards have over 50% load. That tells me both cards are working, and the FPS seem to not change. I am fairly certain this has not always been the case, and may be a bug with the drivers I'm using.

 

[ViRGE]

Like I said above, when I set Single-GPU mode, both cards have over 50% load. That tells me both cards are working, and the FPS seem to not change. I am fairly certain this has not always been the case, and may be a bug with the drivers I'm using.

That definitely sounds like a bug. One of the cards should be as 0% (ish) for work.

 

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