"Stuttering" problem with one of my servers

After my server has been on for a while, not exactly sure how long, people start “stuttering”. When you move, it’s not all smooth and it’s like all glitchy. It doesn’t effect the gameplay at all but it’s just annoying to see yourself going all over the place.

Addons include:

Wiremod SVN
Adv. Teleporter
CSS Realistic Weapons 4.0
DoorSTool
Falco Prop Protection
Freespace_Revolution
keypad
Realistic Fall Damage
Smart Weld
Smart Snap
UClip
ULX/ULib
Waterizer
Weight STool

???

Stuttering like, Network lag?

No, it’s just in-game. My other server is fine, running off the same machine.

Is everything up to date?

It just may-be that the server is fighting for resources that are being used by the game… put net_graph 4 into console and look for sv: ##