turing off selinux makes gnome 60% faster?

[dragoran]

according to this review:
http://distrocenter.linux.com/distrocenter/06/03/08/2321254.shtml?tid=107
"FC5 runs on a 2.6.15 kernel and uses a branded version of GNOME 2.14 as 
its default desktop. Although GNOME 2.14 is roughly twice as fast as 
earlier versions when installed in other distributions, little of this 
acceleration is visible in FC5. A large part of this relative slowness 
is due to the default enabling of SELinux -- turn it off, and GNOME is 
as much as 60% faster."

turing off selinux makes gnome 60% faster...
can this be true?
how does selinux affects gnome perfomance?