A big warning for people using crossfire setup for H7

[crislevin]

Apparently the game doesn't support crossfire (I am unsure about SLI, perhaps somebody can try out). Crossfire setup has near zero scaling.

Not only that, enabling crossfire cause 2nd GPU to be near 100% constantly, consume more energy, and place enormous thermal stress on the card.

In my example, my 295x2 reached very close to thermal threshold (75C) within 20 minutes, with zero increase in fps.

My solution is to use border-less mode, which prevent crossfire from kicking in. I have same fps, and my GPUs are only 55C.

[Marzhin]

We don’t support Crossfire or SLI because Unreal doesn’t. Unreal optimizes a lot by use the result of the previous frame, which is great for single GPU. But doing this prevent the SLI (because the previous frame might be not of the same core). It’s purely technical and actually UE4 doesn’t support it either.

[crislevin]

Thanks for the reply.

I myself played a few UE games before. It really doesn't bother me the crossfire is not supported, since one GPU is more than enough.

The real trouble is that the game right now is using 2nd GPU 100% by default. This causes the card to overheat easily. Even if the game doesn't support crossfire, perhaps its worth checking the code just to be sure players won't get their computers shutting down from time to time because they have a dual-GPU setup.

[Marzhin]

I'll pass the message to the techies of the team

[Dalai]

We don’t support Crossfire or SLI because Unreal doesn’t.
...
It’s purely technical and actually UE4 doesn’t support it either.

OMG!!! It seems I was a student when I first heard about SLI and Crossfire. I am old and cranky now, planning my retirement, and Heroes still can not use those techs. How lame is that?!!

Not only that, enabling crossfire cause 2nd GPU to be near 100% constantly, consume more energy, and place enormous thermal stress on the card.

It's so good that H7 is out before winter! You can at least save on heating expenses. In the summer you would have paid double for conditioning.

[Marzhin]

OMG!!! It seems I was a student when I first heard about SLI and Crossfire. I am old and cranky now, planning my retirement, and Heroes still can not use those techs. How lame is that?!!

What is truly strange is that Unreal, which is *the* 3D engine par excellence, doesn't support it.
According to our main engine programmer, it's because, and I quote, "it’s purely a marketing ploy to claim that 2 graphics gives 200% of the power, but Epic's developers are no fools so they don’t care implementing it". Make of that what you will

[Dalai]

What is truly strange is that Unreal, which is *the* 3D engine par excellence, doesn't support it.
According to our main engine programmer, it's because, and I quote, "it’s purely a marketing ploy to claim that 2 graphics gives 200% of the power, but Epic's developers are no fools so they don’t care implementing it". Make of that what you will

Between Epic people and Crossfire/SLI people someone is obviously wrong. And Crossfire/SLI people have very good both theory and practice.

I personally strongly doubt that there is a marketing ploy with 200% power. Nothing scales like that. Doubling computing power usually results in 50-85% rise in productivity, not 100%. Which is still pretty great.

But neither Epic nor Crossfire/SLI people are responsible for MMH7. Ubisoft is. If MMH7 player (read: Ubisoft client) has a problem with overheating and low performance, pointing to Epic is not the best of moves.

If you still insist that it is - then Ubisoft clients have equally reasonable right to demand the same level of graphics and performance that was achieved by other developers using same engine. Which Ubisoft - we all guessed it - fails to deliver. Again.

[Marzhin]

But neither Epic nor Crossfire/SLI people are responsible for MMH7. Ubisoft is. If MMH7 player (read: Ubisoft client) has a problem with overheating and low performance, pointing to Epic is not the best of moves.

Don't worry, I already forwarded the info about the overheating to Limbic, so they can look into it.
My comment was only related to the lack of support of Crossfire/SLI by the Unreal Engine. Since it's a limitation of the engine itself, there's nothing we can do about it.

[Dalai]

My comment was only related to the lack of support of Crossfire/SLI by the Unreal Engine. Since it's a limitation of the engine itself, there's nothing we can do about it.

And my comment was only related to the usual lack of accountability by Ubisoft. Nobody cares about engines and their limitations. Choose another engine if you need to - that's what you can do.