Lag @ times with low cpuage

[Devilfish]

Anyone get lag at times even tho the cpuage is low in top?
We run 2* 32 player cs source servers on a dedi raq with mani plugin and cpuage is well with in limits! but every now and then people complain about lag even when they are only 2/3rds full. Is this just source code or are there any good server settings to make source work harder and use more cpu giving a smooth game, Ive played around with a few settings max_fps and unlag but with no real change?

Any help is appreciated

Simiancage 217.158.150.50:27035/27045

[Tyrann]

maybe there are some cpu spikes u can't see in top but it can also be the config from your server, and yes the source server engine is still beta ...

[rjerina]

what OS are you running?

i'm running a freebsd 5.3 source server (32 player) and people experience lag all of the time. 100mbit pipe and also my cpu usage is pretty low (never over 50% even when full)