Server lag/ Server rates/tickrate

Hello so i run a popular garrysmod darkrp server its being lagging alot lately and i cant find good server rates to get it running smooth

All my current rates are at default
except i have my tickrate at 33

Could someone tell me good settings to make it run nice

Specs: DDR3 2.9GB Ram, Raid 10, Intel Xeon E3-1230 V2, 1GB Internet Shared Line

Server slots: 42

Startup Command: ./srcds_run -console -game garrysmod -tickrate 33 +maxplayers 42 +map rp_downtown_v4c.bsp

Admin Mod: ULX