So if games have to suport multi GPU setups?

[aham]

How did the voodoo2 sli and multichrome work? or the rage fury or multi gpu ati 8xxx and 7xxx cards

The voodoo2 came out in a time before the internet was like it is today and many games did not see too many if any patches. And multichrome was never main stream by a long shot but works with a lot of games.

The fury and multi GPU 7xxx and 8xxx never saw much any support from game developers ether. 

 

So if everyone says that games need to support multi GPU sets how did all these setups work most of the time if they did not have game developers that supported them?

[Levent]

It always been the drivers, not just the game. Whatever your code is, drivers can interpret it to run on multiple gpus if your game engine supports.

Back then it was more dependent on drivers.

[goto10]

game added support for voodoo accelerator, so you had to select the right environment instead of opengl, direct3d or software rendering

 

which also needed a driver to handle the load sent by the game to speed up the 3d acceleration on games like unreal tournament

 

on that time if the game developer did not added the voodoo glide support, no 3d for you and game had to be run on the cpu only making the 3d acelerator do nothing more than wasting electricity and space inside the case

 

on that time those were not 2 gpus, it was one, doing 2d load and the voodoo doing 3d acceleration when the game supported it

 

later when voodoo added the sli capabilities they made the voodoo also a 2d acelerator, a entire gpu, so they could get rid of the 2d acelerator, those old gpus like trident 2mbs or similar old video adapters because call them accelerators is not fair really

 

o  that time if the game added later a patch to support glide, you had to find a friend that let you download the patch, burn to a cd and install the patch, and also download a newer voodoo driver, because surely the one that came in the box was outdated and wasnt going to work well with the patch the game you downloaded released asking for a newer driver

 

back then support was fin, really fun, make anything work was a wonder

[aham]

16 minutes ago, Levent said:

It always been the drivers, not just the game. Whatever your code is, drivers can interpret it to run on multiple gpus if your game engine supports.

Back then it was more dependent on drivers.

Exactly, at least someone knows how it works.

[Frankenburger]

The way games are rendered are fundamentally different from the modern era and the 1990's and early 2000's. AFAIK, Voodoo cards used interlacing, where one GPU would render every other line. I don't know if there were compatibility issues back then, since that was before my time. More modern multi GPU setups require compatibility layers to be enabled within the drivers. In the early 2000's, it took Nvidia about 2 years to add enough compatibility layers to officially support around 100 games when Nvidia's SLI hit the market.

 

Today is a whole different beast though. Nowadays, there's rendering modes that simply don't work with multi GPUs depending on how it's implemented. Temporal AA is famous for not being compatible with SLI, because it screws with the alternate frame rendering (AFR) mode.

 

Games don't need to "support" multi GPU setups per say, because most of it is still handled by the drivers, but there is a certain amount of responsibility that developers needs to account for when developing a game. If developers use rendering methods that mess with the foundation of modern multi GPU technology, then there's nothing AMD or Nvidia can do about it.

[aham]

Yes you are right, the voodoo 2 and most multi gpu setups up until nvidia brought it back used AFR mode. Today you can still force AFR on dx 11 down to DX6.1 and openGL games and that works for 90+% of the time.

 

I'm amazed that at lest 2 people here know how multi GPU setups work. almost everyone now a days says its dead and the game must support it.