ob_start() and ob_gzhandler

Just wondering what would cause the following: I have a 512/128 cable connection through my ISP that I'm hosting my sites through. I have a 10gb/mo transfer limit (u/l and d/l) so when I saw mention of the ob_gzhandler (and mod_gzip for Apache), that kind of got me interested in it. Anyway, I created a test page, put -just- <?php ob_start(); ?> at the top, then some lines of HTML, and loaded it. I got all the HTML code displayed - shouldn't I have gotten a white screen since I had no <?php ob_flush(); ?> tag at the bottom? This isn't making sense. Then I tried <?php ob_start("ob_gzhandler"); ?> and <?php ob_flush(); ?> at the bottom - same results. Am I doing something wrong? Shouldn't the ob_start() by itself just load all output into a buffer and not display it until I call ob_flush ()? And how would I know if ob_gzhandler works? I'm running PHP and Apache on Windoze, PHP is version 4.2.0 I think, Apache is 1.3.something. TIA Jason Soza