For me the solution was very simple.... Still took me about 4 hours to figure it out....

I wen't on my desktop, right clicked

Settings > Screen > Graphic settings > Looked for ACValhalla.exe > manually chose max (apparently my computer was allowed to choose for it self, which have never been a problem with any other games)... Now I'm playing..

@requisite0

Thank you, everything is updated - is your game working?

I got a killer PC... But I can't even watch the loading/intro scenes without game stuttering... When proceeding to playing the game, I'll get black screen before entering... I 'saw' the entry video or rather lagged my way through it... I tried the same as everyone else I supposed... I bought a new computer, so that I would be able to enjoy this game fully... I took vacation from my work... I bought the ultimate version.... FIX YOUR FREAKING GAME UBISOFT....

As usually I does not expect Ubisoft to fix anything for the next 4-6 months... Does anybody at all got luck with playing this game on PC?? Did anyone with similar troubles find a way to fix it?

I play Odyssey and most other games with ultra settings and max fps....