Anything that affects the performance on IBM i will usually fall into one of the following categories:
Generally speaking, if you have badly set macro performance factors, your machine will run very badly - but it can be easily and cheaply changed to run much better.
Changes made to an individual macro performance factor will usually produce a large and immediate improvement.
With micro performance factors the reverse is often true. If you have a lot of badly set micro performance factors, they will tend to "accumulate", causing your machine to run badly. It may be very difficult and/or expensive to change these factors to improve your machine performance.
Changes made to an individual micro performance factor will often produce only very slight improvements in performance.