auto sweepers impact performance hard

Its most likely not the sweepers but the rails. They are not multithreaded yet (Klei had problems with the code). So the impact of them is huge. 

And due to the fact, your dupes wont feed all of them at once, the impact drops.

No i tested it

Rails yes impact performance but not like sweepers

I just put storage bins and kilns and auto sweepers without rails and it impacted performance really hard

And the kilns has no dupe access

Thats weird indeed. I use sweepers for everything possible, and there is no impact whatsoever. Do you use mods?

Yes but not for sweepers or rails

Changed Status to Known Issue

There indeed is a performance issue specific to sweepers, though it is also dependent on some other factors that are not intuitively related, which is why SharraShimada might not be seeing it. This will be addressed in a future patch.

Changed Status to Fixed

The next update to the testing branch will have an improvement to the sweepers' performance. As with all performance issues, YMMV depending on hardware and the specifics of the colony, but I expect you would see some improvement in your test.