File writing performance?

[David C.]

Howdy folks,
I guess I could do some bench testing, but maybe someone out there can
save me some time if they already know the answer to my question,
which is:

When saving data to a file (or a group of files), is there any type of
performance loss or gain by using the -->open file -->write to file
-->close file methods, rather than just using the URL keyword format
that I'm currently using?

I have a proprietary app that I wrote for a friend who seems to be
having some performance related issues, so if it is possible I would
like to improve the time it takes to write a few large files to disk.
My friend is running Windows 7 primarily.

Best regards,
David C.