I'm having issues regrading performance with this game, I am running on RTX 2080, i7 9700k and 16RAM.
I play on 3440x1440p and even tried 2560x1440p just to see the difference, "surprsingly" it did not.. the game runs on the Lowest preset with 60FPS in the least demanding areas, when I raid or go to a bit of a crowded spot I reach to a minimum of 45FPS.
I contacted the support via Case and what they told me was: "It's under invastigation".

But, I watched some videos online and I saw some people playing with the same specs as I and still reach a stable FPS of 70 on Very High preset, how is this possible?
Help would be appreciated!

The game I believe natively uses TAA as it's only Anti Aliasing option which is a very demanding AA. I've discovered forcing Nvidia to handle the AA via Nvidia control panel has improved my performance remarkably. Set AA to 2x in NV control panel and the games AA to low. The game image will already look better with Nvidia's AA. Also the games textures are very demanding as were shown in a performance analysis video. I've found forcing Anisotropic filtering in NV control panel provided another substantial performance boost. Image sharpening also helps to makes the natural blurriness of the game sharper and better looking.

I also play at 3440x1440 with a 2080 Ti, 8700K and 32GB RAM. There are some spots in the game I am finding the performance still to be terrible despite my tweaking through NV control panel. The game certainly needs some improvements to the performance. As we all know an erratic frame rate really does break the immersion. Hope this helps for now.

@kolack thank you for the reply and for the suggestion, I will give it a shot

@kalasdev
Let me know.

@kolack I was waiting for the new patch as well to answer this, unfortunately no improvement either way. Ubisoft made me question my future purchases from this moment, I'm an active member since 2014 haha, I should have known better.

@kalasdev
What are the rest of your graphics settings?

@kolack I play on lowest preset and maintain a framerate of 60 which is ridiculous due to my rig.

@kalasdev

Running the low preset may actually reduce performance, it might introduce some kind of bottleneck. These are my settings:

AA - Low - Enhance application setting 2x (via Nvidia control panel)
Character textures - High
Clutter - Very High
Depth of field - Off
Display - Fullscreen
Environment textures - High
Screen Space Reflections - On
Shadows - High
Volumetric Clouds - High
Water - Medium
World Details - High
Resolution Scale - 100%

You have a 2080 so my 2080 Ti is a bit more powerful. However I would try something similar to my settings. For res scale you could try 90% and see if the image is still to your liking. Don't forget to override Anisotropic Filtering in Nvidia Control Panel to 2x as well. Let me know your results.

Edit: You could also try reducing the FOV to see if that helps.

@kolack Thanks, I'm testing the settings right now.

Also set these in Nvidia control panel:

AA Mode - Override (before I suggested the enhance setting)
Texture Filtering - Anisotropic optimization - On
Negative LOD Bias - Allow
Texture Filtering Quality - Performance
Trilinear optimization - On

@kolack yep they are on by default for me and perofrmance does seem a bit better with the in-game settings, thanks.

@kalasdev

You need to add the AC Valhalla.exe as a profile to Nvidia control panel (under Manage 3D Settings) and override the options I've mentioned to those settings.