As we’ve already said in our PC Performance Analysis, SLI scaling in Rise of the Tomb Raider is messed up. Well, not anymore. 3D Center’s ‘Blaire‘ has found some new SLI bits and with some minor tweaks he was able to enable proper SLI support. And we are happy to report that this solution works, as our GTX690 was indeed used to its fullest thanks to this new profile.

In order to enable this new profile, you will need the NVIDIA Inspector Tool. Search for Rise of the Tomb Raider’s profile and change its SLI bits (DX11) to 0x080002F5. Then, press on the magnifier icon in order to reveal NVIDIA’s Undefined options. Search for 0x00A0694B and set it to 0x00000001.
And as you can see below, SLI scaling works wonderfully now thanks to this new custom SLI profile!

На скриншотах smaa сглаживание.

Прибавляет более 20 фпс, просадок почти нет и они до 55-54 фпс. Можно играть даже с ccaa 2x сглаживанием будет примерно 46 - 55 фпс.
Наслаждайтесь.

Материал взят отсюда:
http://www.dsogaming.com/news/rise-of-the-tomb-raider-sli-fix-found-offering-95-sli-scaling-on-two-nvidia-gpus/