performance decrease in case of activity chaining

It totally depends usage of chaining.
Think of it like waiting in line, if some activities involve complex calculations, database interactions, or there are just too many forms in a row, users might experience delays. This is because Appian holds onto resources for the entire chain, similar to how a long line at a store can slow down everyone. To avoid this, keep your activity chains short and simple, and consider using asynchronous execution (working on tasks in the background) for resource-intensive activities.

It totally depends usage of chaining.
Think of it like waiting in line, if some activities involve complex calculations, database interactions, or there are just too many forms in a row, users might experience delays. This is because Appian holds onto resources for the entire chain, similar to how a long line at a store can slow down everyone. To avoid this, keep your activity chains short and simple, and consider using asynchronous execution (working on tasks in the background) for resource-intensive activities.

Suppose with the same scenario we are not doing activity chain for complex calculations and database interaction . In that case also resources will be needed to perform the task .How it will increase performance . I mean the work arounds will be same but activity chaining is not enabled in second case

Activity chaining holds resources for the entire chain, even for slow activities. Removing chaining lets Appian free up resources sooner and potentially run things more concurrently, improving performance.
Workarounds like simple forms and asynchronous execution are still important for optimal speed.
I hope that answers your doubt.

yes, Thanks .