APXS Performance question

I have a development box running RH 6.1/Apache 1.3.6/PHP 3.0.12 (as a module). The machine is a P166 with 40MB of ram. When I run certain scripts they usually take about .8 secs on this machine to run, which is in line for the complexity of the script and hardware in the machine. I wanted to upgrade the machine to run PHP 3 and 4 at the same time, so I was going to go the apxs route. I recompiled Apache 1.3.12 and 3.0.14 and configured them as instructed. Everything works for PHP3 (I haven't add 4 yet) but now the scripts that took .8 secs take 1.4+ secs to run. I am wondering is there a performance hit when using apxs as opposed to a straight module setup? Can PHP4 be run as a module or just through apxs? Thanks, Michael