Apache or IIS

[ggiaisme]

Hi everyone, I am using a window server for website of my company with IIS. We want to create some more websites

So Should I change to Apache or keep using IIS. I just afraid of low speed if deploy morsite coded in PHP

[edit by Altrea: moved to the English part of the board and removed URLs. Spam is not allowed here and the URLs didn't contain any worth full information for the topic]