Possible solution for better SLI utilization

[A Barbarian]

Update2 :
After more SLI testing, it seems that the 'Particle Effects' can cause the SLI utilization to bug out. Since having them set to max performance I haven't noticed any desynch between the 2 graphics cards.

Also, after moving from 7970 crossfire to 970 SLI, I noticed that crossfire configuration was lacking a lot of fire (particle effects) even on the campaign map. But crossfire scaling was working fine.

Atm:
Crossfire: perfect scaling, no desync between cards but no proper fire (particle) effects
SLI: with higher particle effects, possible desync between SLI cards


Outdated:
Update: It seems SLI utilization can randomly break down or reinstate itself. I thought I found some settings which triggers it but it's more like random.

I just moved to a SLI GTX970s and noticed that SLI performance is very bad. After some investigation i found that the 'screen space reflection' and SSAO setting often (but not always) destroy SLI utilization. I guess it's a driver and/or game engine problem.

Until it's fixed, just turn off Screen Space Reflection and SSAO.

[Mr.Freud]

I've noticed the same thing.

[A Barbarian]

Hmmm, I did some more testing and there seems to be more funny stuff to be going on. Sometimes it seems SLI get's into proper gears and sometimes not. During the same game session and even the same replay, just by switching settings forth and back. But I am not sure about that yet.

Otherwise for the 2x970s I applied slight DSR in combination with 2xMSAA and dialed down 'grass quality' and 'particle effects' one notch. In addition I limited the framerate with Afterburner to 28fps and I am quite happy with that. Finally the fire, smoke and dust effects are visible. On my 2x7970s they were almost completely missing.

Here is a quick screenie:

Spoiler Alert, click show to read: 

[SPARTAN VI]

Sometimes it seems SLI get's into proper gears and sometimes not.

That was my experience as well. I found that running the Londonium benchmark, then ESC'ing out would then have proper SLI scaling for subsequent sessions.

Not sure what was flipping it on/off, but I had enough of it. I traded my SLI setup for a single GPU setup.

[A Barbarian]

Ok, it seems more like random. If SLI works, performance is great with 2x970s.

New favorite settings (when SLI works, lol):
3840x2160 DSR
Extreme Preset (modified, see below)
- 2XMSAA instead of 4x
- SSAO off
- screen space reflections off

With that I get 33fps avg on 2x970s

[A Barbarian]

Tried latest NVIDIA Beta drivers 350.05. But exactly the same problem.

When launch the benchmark sequence the first time after starting Attila, SLI utilization breaks down exactly at the same point every time. When I run the benchmark a 2nd time without restarting Attila it usually works.
It also works the first time in the benchmark if SSAO and screen space reflections are off. But SLI might still break down in another scenario.

Could still be a driver problem because I didn't have that problem for crossfire with my 2x7970s.

[A Barbarian]

New update, it seems particle effects are the main issue (updated original post).