Nginx without access log

[etrader]

Obviously nginx needs a time (even very short) to write access and error
logs upon every request. Thus, theoretically, removing access and error
logs from nginx configuration should speed up the web server.
Surprisingly, when I did so, the load of my website became slower. Is it
normal?

NOTE: I know that logs are useful and needed for real experiences; I
just try to better understand nginx as my beloved web server :)

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,219454,219454#msg-219454