this is a dx12 issue
 
as jayz said on dx11 3-way and 4-way sli are not affected
 
developers wanted MORE control over SLi - hence MDA mode and LDA modes

 
Its the Software developers that wanted this so they are responsible for this - and so should they be- since SLi basically WAS a developer/OS optimization issue
now they have more control over methods and optimizations - Nvidia only has to provide 2 way optimized ...most users don't go beyond 2 cards(sli) and maybe physx
most games don't scale well beyond 2 way anyways
 
 
 
you also have microsoft as a contributing factor - dx12 - win 10 - another person/company for developers to figure out how to handle 3-way and 4 way optimizations with 
more people more issues
 
now the developers can determine they own way to optimize dx12  Sli above 2 way - without Nvidia and with Microsoft only
remember dx12 brought new features like unified memory
 
gets the extra person/company out of the room...easier to make progress
 
furthermore CPU bottlenecks are the issues coming up - gpu tech is overwhelming cpu tech and are hitting bottle necks at the cpu
and it's only gonna get worse 
 
as jay said his 5960x was bottlenecked
 
 
 
 

Xavier Zepherious
this is a dx12 issue
 
as jayz said on dx11 3-way and 4-way sli are not affected
 
developers wanted MORE control over SLi - hence MDA mode and LDA modes

 
Its the Software developers that wanted this so they are responsible for this - and so should they be- since SLi basically WAS a developer/OS optimization issue
now they have more control over methods and optimizations - Nvidia only has to provide 2 way optimized ...most users don't go beyond 2 cards(sli) and maybe physx.
 

Correct developers do want more control, however, nvidia has clearly chosen to only support 2 gpu's in lda implicit mode. 
 

Xavier Zepherious
most games don't scale well beyond 2 way anyways

 
Incorrect. It depends on the resolution you're running.
 

Xavier Zepherious
furthermore CPU bottlenecks are the issues coming up - gpu tech is overwhelming cpu tech and are hitting bottle necks at the cpu
and it's only gonna get worse 
 
as jay said his 5960x was bottlenecked

Incorrect again. Again this depends on the resolution you're running. Jay was talking about his valley benchmark scores @ 1080p.

In LDA Mode, each GPU’s memory can be linked together to appear as one large pool of memory to the developer (although there are certain corner case exceptions regarding peer-to-peer memory); however, there is a performance penalty if the data needed resides in the other GPU’s memory, since the memory is accessed through inter-GPU peer-to-peer communication (like PCIe). In MDA Mode, each GPU’s memory is allocated independently of the other GPU: each GPU cannot directly access the other’s memory. LDA is intended for multi-GPU systems that have GPUs that are similar to each other, while MDA Mode has fewer restrictions—discrete GPUs can be paired with integrated GPUs, or with discrete GPUs from another manufacturer—but MDA Mode requires the developer to more carefully manage all of the operations that are needed for the GPUs to communicate with each other. By default, GeForce GTX 1080 SLI supports up to two GPUs. 3-Way and 4-Way SLI modes are no longer recommended. As games have evolved, it is becoming increasingly difficult for these SLI modes to provide beneficial performance scaling for end users. For instance, many games become bottlenecked by the CPU when running 3-Way and 4-Way SLI, and games are increasingly using techniques that make it very difficult to extract frame-to-frame parallelism. Of course, systems will still be built targeting other Multi-GPU software models including...
 
in fact some games will continue to deliver great scaling beyond two GPUs.
 
excerpts from
http://www.guru3d.com/articles-pages/nvidia-geforce-gtx-1080-review,4.html 
 
 
it will only get worse... volta will definitely be a problem for cpu's because Intel is not offering big scale increases
 
if there's bottlenecking on two pascals then one volta will do it 

Exactly Sajin.  With resolutions some of us are running, the last thing we worry about is a CPU bottle-neck.

Tom Petersen just said updating your firmware of your 1080 will allow 3 way and 4 way sli.

Updated post #182.

Gonna just quote JayzTwoCents I think it sums up this whole situation well, "Nothing is more frustrating than people that pretend to know [insert alternative word for crap] that they really don't." NVIDIA has never really truly supported (or wanted to for that matter) SLI past dual cards as it's always been a thing that had much room for improvement. Gotta love all the reporters out there crying wolf since the first millisecond this was uttered.

mike406
Gonna just quote JayzTwoCents I think it sums up this whole situation well, "Nothing is more frustrating than people that pretend to know [insert alternative word for crap] that they really don't." NVIDIA has never really truly supported (or wanted to for that matter) SLI past dual cards as it's always been a thing that had much room for improvement. Gotta love all the reporters out there crying wolf since the first millisecond this was uttered.

So nvidia just adds dual sli fingers to their cards for no reason? Interesting.

Sajin

mike406
Gonna just quote JayzTwoCents I think it sums up this whole situation well, "Nothing is more frustrating than people that pretend to know [insert alternative word for crap] that they really don't." NVIDIA has never really truly supported (or wanted to for that matter) SLI past dual cards as it's always been a thing that had much room for improvement. Gotta love all the reporters out there crying wolf since the first millisecond this was uttered.

So nvidia just adds dual sli fingers to their cards for no reason? Interesting.

 
Because tons of people wanted it, yes. Even Jay in his latest video said it was something they never wanted or technically recommended doing. Just because it's there doesn't mean they were all for its existence.

mike406

Sajin

mike406
Gonna just quote JayzTwoCents I think it sums up this whole situation well, "Nothing is more frustrating than people that pretend to know [insert alternative word for crap] that they really don't." NVIDIA has never really truly supported (or wanted to for that matter) SLI past dual cards as it's always been a thing that had much room for improvement. Gotta love all the reporters out there crying wolf since the first millisecond this was uttered.

So nvidia just adds dual sli fingers to their cards for no reason? Interesting.

 
Because tons of people wanted it, yes. Even Jay in his latest video said it was something they never wanted or technically recommended doing. Just because it's there doesn't mean they were all for its existence.

Guess they're sending the wrong signals then.