Anyone run a HL Orangebox Linux Server?

[Valkyrr]

I just tossed up a HLDS Orangebox server for TF2 on CentOS 5 and I'm looking for some tweaks, mods, suggestions, hints etc.

Here's what I've got:

CentOS 5 with kernel 2.6.18.xx Single Processor Kerneel
CPU: 2.8Ghz P4
Memory: 2.5G DDR

I've adjusted the sv_maxrate and the updaterates. I've also added a cron job that renices the srcds process to -20 every 5 minutes.

I'm running CentOS in init 3 (terminal mode) no Xserver running.

Recently I had about 16 ppl on the server and our ping rates started spiking to around 1000 and the CPU seemed to be going bonkers.

I'm looking for the following:
Memory/CPU tweaks for linux
CentOS specific tweaks?
HLDS tweaks?
Other suggestions?