PHP as CGI or Sapi on IIS?

[Anon]

Which will yield the best performance, installing PHP as a CGI or SAPI module on IIS 5? We get 15,000 unique visitors a day (not hits), so performance is important. We are converting from COld Fusion to PHP and the server couldn't handle it yesterday.

We considered installing Apache instead of IIS, but Apache.org said...
"Warning: Apache on NT has not yet been optimized for performance."

Any tips is appreciated. Thanks.

[Anon]

I have had experience with all the diffrent combinations of software.

my verdict:

Fastest by far is a well configured apache isapi build, although an out of the box IIS with php sapi can be faster depending on the configuring of apache...

in short:
if you know what your doing then APACHE +PHP SAPI module is by far a better choice