Are there downsides to increasing undo steps?

Question

Will setting the undo steps to 256 make the software slower by any means?

Answer 1

Unfortunately, as is often the case with performance questions, the answer is "it depends". In this case it depends on how much memory you are using in your Blender instance and how much physical memory you have on your computer.

I use 256 and have never seen a problem with performance as a result, but I also have 32GB of memory available to Blender and I rarely have an instance running that is using more than 8GB.

If you are going to see a problem it will be because your Blender instance will grow to need more memory that is physically available and will have to move pages back and forth between RAM and whatever secondary storage you have for paging, probably a hard drive or SSD.

A lot of this depends on the nature of the operations you perform. The more state that Blender has to save to be able to undo an operation the quicker the undo buffer will expand.

There are no other performance penalties from changing the number. The performance of the undo or redo operations are that of pushing things onto or popping them off of a stack, which is independent of the stack size.