[CentOS] SELinux resource hog

Spinning off from the other thread about SELinux, I just tried to
re-enable SELinux on my personal server hosting just email and forum
for a small local community.

Average load for this Intel Core 2 Duo box with 2GB of ram (usually
with some 1GB free) was generally below 0.4 for the last 24hrs,
averaging 0.23 based on MRTG.

Once I did setenforce 1, load shot through the roof to fluctuate
between 3 to 5. As per my past experience setroubleshootd started
chewing up ram more than 600M and 500M worth of virt and res based on
top. The server started crawling and php apps stopped communicating
with mysql.

I had to kill setroubleshootd in order to return things to normal.

This again reflects my original experience with SELinux: massive
resource hog and this is just a lowly loaded webserver. Naturally it
seems to me that this doesn't seem like it should be the norm.

What could be going on here or rather what could be wrong here?