YouTube’s ‘Candyland’ has released a video, showing some of the graphical differences between Assassin’s Creed: Unity and Assassin’s Creed: Syndicate. Unity was criticized for its framerate issues and really high requirements and in order to improve things in Syndicate, Ubisoft decided to remove/reduce a number of effects.

Assassin's Creed Syndicate recently got a 60 FPS update, allowing the game to run at 4K and 60 FPS on PS5, PS5 Pro, and Xbox Series S|X.
It is amazing what's available. Blue Dragon. Binary Domain. AVP. Chaos Theory. Lots of gems to be had.
There is no re-start option (that I can find). Since I've already finished the story years ago, I can't re-start it to check the new update.

Revisit the Assassin fantasy and take down your enemies more smoothly than ever on Assassin's Creed Syndicate’s free 60 FPS patch.
AC Unity next Please! despite the technical issues it was a good game even though it was too ambitious for PS4 and Xbox One the graphics hold up well. I would love to see it on PS5 and Xbox Series Consoles
Is Syndicate any good? I own them all since they end up in the bargain bin but I haven’t played one through since Black Flag
If you've read my comments here before, you know damn well that I'm always quick to mock Ubisoft, but in this case, its good news. Glad to see that Syndicate went from being almost broken on PS5 BC, to receiving a free 60 FPS update patch.
While this game did have grind elements, and skill trees, it wasn't exhaustively grindy like the later games would end up being. The London setting was amazing, too, and the soundtrack by Austin Wintory was fantastic. I really liked playing as a brother and sister duo as well.
It was a good game, and the last one in the series I truly enjoyed.
Why are the patch sizes so different between Xbox Series and PlayStation 5? Its a 35 GBs difference.
Patch notes:
Xbox (~31.8 GB)
Xbox Series X
4K resolution at 60 fps
Xbox Series S
1080p resolution at 60 fps
PlayStation (~0.75 GB)
PS5 and PS5 Pro
1080p resolution at 60 fps
4K resolution at 60 fps

Shaz from GL writes: "Assassin’s Creed Unity is looked at as one of the worst in Ubisoft’s iconic franchise. But playing it nearly 10 years later reveals it may just be the best"
Gamers:
"Unity runs at sub-20fps. Fix this shit!"
*Ubisoft makes necessary changes to ensure it doesn't happen again*
"This game looks worse than the last one! WTF!"
Still looks pretty good to me. Does it performs better than Unity? That's a much more important question.
At least Syndicate works.
Framerate and gameplay trumps graphics. When will people understand that simple truth?
it still looks great and plays even better.