Traffic graph showing in/out traffic a lot less than it supposed

[Switch]

Yes, my traffic graph is showing about half of speed of true traffic. Might this problem relate to my systems *time advancing or is it odd bug that I'm experiencing and no one else :)?

*****http://forum.pfsense.org/index.php?topic=1253.0

[hoba]

In case your clock is really inaccurate values per second won't be calculated right. try to measure the download speed at the client and compare it to what the webgui reports.

[Switch]

I measured and it is exatly half. I downloaded at max speed and it showed 4 Mbps and it should be 8 Mbps. That's it then. System time is then double the correct speed.