The only difference between ATX and Micro ATX is that Micro ATX boards are a bit shorter, having the bottom slots removed. Removing PCI slots has no affect on performance.
<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>