Dolphin, SLI, and compatibility bits

[svjness]

Heya, first post here. Through the googles, I have stumbled upon a few topics here about Dolphin and SLI, and yes, I know that it does not work. Or rather, you can add the compatibility bits and both GPU's will be under load, but you won't see any performance gains with Dolphin at least. Mostly out of curiosity, I did indeed get it to work and both GPU's are under load ( http://starmansuper.com/xeno/xenosli.png ). My understanding is that the benefits of SLI won't be seen unless the app is written to support SLI, which requires the participation of Nvidia.

The question I have is more in a general sense of how people are uncovering compatibility bits for games, or why someone has even bothered to find SLI compatibility bits for Dolphin. Do the compatibility flags for Dolphin force it into AFR or SFR? If there is no performance gain to forcing an app into SLI, would there be less of a load (temperatures) on both cards as opposed to rendering it on 1 card?

[NaturalViolence]

svjness Wrote:which requires the participation of Nvidia.

Not true.

svjness Wrote:The question I have is more in a general sense of how people are uncovering compatibility bits for games,

Through comparison. Observing cause and effect. Etc. I don't think there is any actual documentation on it (or at least anything good enough to be worth reading).

svjness Wrote:or why someone has even bothered to find SLI compatibility bits for Dolphin.

Because that doesn't make any sense. You can't magically make dolphin scale with SLI by changing some compatibility bits in the driver.,

svjness Wrote:Do the compatibility flags for Dolphin force it into AFR or SFR?

What flags are you talking about? Dolphin doesn't have any official compatibility code.

svjness Wrote:If there is no performance gain to forcing an app into SLI, would there be less of a load (temperatures) on both cards as opposed to rendering it on 1 card?

Possibly depending on how it was setup by the drivers. But doubtful.

The way SLI works is directly opposed to the way that flipper/broadway (the GC/Wii GPU) emulation must work. It will never work properly no matter what bits you use. PC games on the other hand do not have this problem.

[tuanming]

No need for SLI/Cross-Fire when you can get a single high-end card.

[svjness]

Since I posted this I've been reading up on the nvidia inspector documentation (which is in German) to wrap my head around how this is supposed to work. I think I may have a slightly better idea. The thing that sent me down this rabbit hole was this thread: http://forums.guru3d.com/showthread.php?t=379960

There are Dolphin compatibility bits provided, which were originally posted on a German forum http://www.forum-3dcenter.org/vbulletin/showthread.php?t=509912

This is what spiked my initial curiosity with "forcing" SLI. For example, DayZ standalone does not currently support SLI. I did however find this http://steamcommunity.com//sharedfiles/filedetails/?id=205916418 which appears to be using parts of the ArmaII profile(DayZ is built on the ArmaII engine), and SLI does work from my testing. I saw no real change with the framerate, but the load was split between both my GPU's, so my computer didn't sound like a rocket taking off when I was playing.

I see that Dolphin is a completely different scenario.

[cosmoruski]

The other question would be: why support SLI/Crossifre?
It would be a solution for a non existing problem, since every midrange GPU can handle dolphin

[NaturalViolence]

At what settings though?

Almost any gpu can run dolphin sure. But the faster your GPU is the higher you can push your settings.

svjness Wrote:Since I posted this I've been reading up on the nvidia inspector documentation (which is in German) to wrap my head around how this is supposed to work.

Unfortunately that document doesn't contain any information about what these bits actually do. So it's pretty useless for your purposes.

svjness Wrote:There are Dolphin compatibility bits provided, which were originally posted on a German forum http://www.forum-3dcenter.org/vbulletin/...p?t=509912

The user in question provided no information about why he chose those bits, what they do, or their effect on dolphin.

svjness Wrote:This is what spiked my initial curiosity with "forcing" SLI. For example, DayZ standalone does not currently support SLI. I did however find this http://steamcommunity.com//sharedfiles/f...=205916418 which appears to be using parts of the ArmaII profile(DayZ is built on the ArmaII engine), and SLI does work from my testing. I saw no real change with the framerate, but the load was split between both my GPU's, so my computer didn't sound like a rocket taking off when I was playing.

I see that Dolphin is a completely different scenario.

Yup. You get lucky sometimes with PC games using common engines.

[Zanoh]

(04-03-2014, 01:48 AM)cosmoruski Wrote: The other question would be: why support SLI/Crossifre?
It would be a solution for a non existing problem, since every midrange GPU can handle dolphin

Because I game at 4K/UHD. My single 970 can only handle 4K at 30FPS and it hurts games required to run at 60FPS.

[mbc07]

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