> 204MB on disk -- that's small.
> 1GB of RAM -- that's tiny.
> Every hour tables get updated with hundreds... -- yawn! (Hundreds per _second_ gets exciting.)
> high CPU usage -- poorly optimized queries and/or missing indexes.
Nothing you say says that you must use one Engine or the other.
To assist in analyzing slow SELECTs, please provide
* SHOW CREATE TABLE tbl\G -- engine, indexes
* SHOW TABLE STATUS LIKE 'tbl'\G -- sizes
* EXPLAIN SELECT ...\G -- clues of inefficiencies
* SHOW VARIABLES LIKE '%buffer%'; -- cache size
and surround them with [ code ] and [ / code ]
If you choose to convert to InnoDB, read
http://mysql.rjweb.org/doc.php/myisam2innodb
Read this for memory allocation, but shrink down the values a bunch, since it was not written for "tiny" machines:
http://mysql.rjweb.org/doc.php/memory