Keep Web page size at or below 30,000 bytes for an acceptable downloading time. The maximum allowable page size is 30,000 bytes in order to achieve desired response time of 10 seconds using a modem . Use frames only when other design solutions are not adequate. Frames may take longer to design, develop, and maintain. Splitting a page into frames can be confusing for users since frames can break the fundamental user model.
Frames make a Web site difficult to use, and can prevent users from emailing a URL to others.
A Designer's Guide, North Andover, MA User Interface Engineering.