Quartus® Prime Standard Edition User Guide: Design Compilation

ID 683283
Date 10/22/2021
Document Table of Contents

1.10.1. When Timing Performance May Not Be Preserved Exactly

Timing performance might change slightly in a partition with placement and routing preserved when other partitions are incorporated or re-placed and routed. Timing changes are due to changes in parasitic loading or crosstalk introduced by the other (changed) partitions. These timing changes are very small, typically less than 30 ps on a timing path. Additional fan-out on routing lines when partitions are added can also degrade timing performance.

To ensure that a partition continues to meet its timing requirements when other partitions change, a very small timing margin might be required. The Fitter automatically works to achieve such margin when compiling any design, so you do not need to take any action.