Drupal installation creates innoDB tables even though myIAM is set as default in my.ini
Drupal overrides the default to set it to innoDB because innoDB is a better choice for Drupal in many cases. Two main reasons for this:


InnoDB supports transactions; MyISAM doesn't.
When a row in a MyISAM table is being updated, the entire table is locked, so no other process can write to it. InnoDB locks rows in tables, rather than entire tables. For example, on this site, if many people are writing to the comments table at the same time, they would have to wait in a queue if the table were myISAM, but with innoDB, multiple writes can happen simultaneously, provided they're not to the same row in the table. This has obvious performance ramifications.


If you absolutely have to, you can edit the information schema table in mysql to set all the tables to MyISAM, but make sure you know what you're doing...