stream_get_contents() quite slow

Hi guys, I'm using stream_get_contents() to parse content of an HTTP session I opened with fsockopen. My requests headers is just fine and transmission is OK : (0.0007s) But when I read the HTTP answer with stream_get_contents(), it lasts about 2.5s ! The webpage is about 5 kB. The connection is opened on the box and ... itself. I use some OpenVZ on the machine. If I use links on commandline to test speed (or even ab) the webpage is loaded about 0.6s ! But I need to use stream_get_contents() to continue on the opened connection to get the response of my specific request. I don't know where to look for about this slow down... Regards, Francois.