Replicated MySQL write performance query
This depends on the query and the binary log format.

An UPDATE query that fetches lots of rows and changes very few will in binlog_format=ROW end up as UPDATE table SET x=y WHERE PK=z so will have a lower CPU/IO overhead. If it was using binlog_format=STATEMENT exactly the same query would end up on the slave.

Conversely a UPDATE query that updates a large number of rows, UPDATE table SET status=Fixed WHERE date &lt; NOW() will generate a large number on binary log entries (for each primary key) and might be slower in binlog_format=ROW than statement.

There's a good document on this in the mysql manual

Based on your galera tag, and the known limitations, you'll be using binlog_format=ROW and each table will have a primary key. Take note regarding transaction size so to avoid stalls due to large updates.