Way of conclusion information through variable

Hi, I cause a doubt my direction of use of PHP. I am develop system of building of web-site (http://sbs.wpdom.com/). In this system information of a page is first prepared in variable ($out), but is afterwards translated to user. Can such way be a reason of irrational using a memory (and other resources), can bring about excessive loading of a server? Respectfully yours, Richter