Regularly clone/backup 2 MySQL databases unidirectionally from PC to Laptop both running Windows I have a PC running Windows XP with a custom ERP system and MySQL Server 4.x (A) and a Laptop running Windows 10, same MySQL 4.x and same custom ERP (B). I'm afraid I can't upgrade PC nor MySQL, etc. Can't touch anything.

I installed SQLYog Ultimate (Workbench/Navicat don't like this MySQL version) on laptop and tried scheduling an unidirectional database syncing job from (A) to (B).
It works, but the problem is that SQLYog compares table by table, and when different, copies record by record and this takes hours to complete, because databases to be cloned from (A) are 1.5 and 2 gb each

I've been searching other ways I could setup something in laptop to regularly (once or twice a week through Windows Scheduler) clone a database directly from (A) to (B) without user intervention, but I've run out of ideas.

Any clues? Thanks
You need to set up MySQL replication.
In your case, can use the following documentation for version 4.1

http://ftp.nchu.edu.tw/MySQL/doc/refman/4.1/en/replication-howto.html

An additional recommendation, upgrade those servers to a newer version.