In the final building, The Transformatory there are many eggs placed on the outer ring. Hundreds of eggs, under each egg there is a purple void graphic.
Each individual swirly effect tanks FPS a lot and combined, there’s upwards of 90% loss in performance for medium-range machines. Please replace them with something else less terrible because they serve no gameplay purpose and aren’t interactable. FPS tax is felt even when they’re outside of your field of view.
There are many other places in the game where this swirly ground effect is used and the general rule is - larger the radius, the worse FPS tax gets. Some players may not notice but the problem is prominent for medium-range machines. Most of these graphics serve no gameplay purpose, aren’t interactable, don’t hurt the character or cause negative side effects if you chose to keep standing in them. It’s just aesthetics at cost of enjoyment.
A similar effect is used in several Delves (ground web graphics, gray). In previous expansions it was mostly for ice and void effects. All of these cause equally bad performance.