Is php 5.0.4 using isapi unreliable?

Hi, We have a Windows 2003 server that seemed reliable using php as a cgi, then due to placing authentication on directories, we needed to switch to the isapi method about three months ago. The server reboots randomly maybe five times per week, but never outside office hours. I have read articles suggesting the isapi module is unreliable, is this still the case with php 5? Thanks.