php-cgi bad performance

[ergonum]

Heya guys,

I wanted to use the nginx server application for my new webserver, because apache2 was totally unperformant.
(Im on AMD64 with debian etch)

I used this tutorial:
http://www.howtoforge.com/installing...debian-etch-p2

To setup nginx with fast-cgi.

I just setup a testserver to play a bit around.
Currently I'm experiencing a strange behaviour of the cgi processes.
Nginx is perfectly working.

But my php-cgi processes are going mad:


PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
15100 www-data 20 0 235m 17m 3076 R 46 0.6 0:51.55 php-cgi
15097 www-data 20 0 235m 17m 3076 R 44 0.6 0:57.14 php-cgi
15099 www-data 20 0 233m 15m 3076 R 40 0.5 0:51.38 php-cgi
15134 www-data 20 0 232m 14m 3076 S 36 0.5 0:49.13 php-cgi
15098 www-data 20 0 232m 14m 3076 S 28 0.5 0:55.42 php-cgi

My php-cgi cpu usage is always around 40-50% even if I'm not accessing the site.
When I relaunch the cgi processes they are at 0%, but with each request the cpu usage is growing.

I can leave the site 10minutes idle, but the cpu usage won't go down.

Any tips what I can do about this?
Thanks in advance, and sorry for my bad englisch.