htm vs. php problem

The company I work for uses .htm extensions with their php code. There
is one page which has quite a few querys that I am having problems
with. With the .htm extension it will take 30+ seconds to load the
page and, for example, will pull approx 30 rows from the db. If I just
change the extension to .php, it takes less than 1 second to load the
same page, and will pull over 300 rows from the db. Any ideas why this
is happening?

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