Unreasonable load with bots

[Appl3]

So recently I was given access to a server run by a friend. I was going to use it to run a private mod called Zombie Onslaught (similar to the NotD ZombieHell in some ways). Note that this mod has run on a half dozen servers since its release, always quite stable at 30-34 bots & 16-20 players. Not one of those servers was as powerful as the current one.

I had many issues with it, cpu usage would always shoot to 99-100% and stay there nearly all of the time. To find the problem, I used the usual method of removing modifications one by one until nothing was left. I removed EventScripts, SourceMod, and everything else I had. Server ran fine. Eventually I narrowed the problem down to bots.
For some reason this server refuses to run more than 24 or so bots without massive lag spikes.

Server:

Dual 2x3.2GHz Xeons (as in a pair of dual-core cpus)
Two GB RAM (not entirely sure of specifics, high quality stuff for sure)
Some 15k SCSI HDDS
OS: CentOS 5.x
Kernel Version: 2.6.18
GCC Version: 4.1.2
GLIB Version: 2.5

So I load up a vanilla srcds. Here's the server.cfg, which is the single thing I modified.

Code:

hostname "Test"
bot_quota 24
bot_add

My starter:

Code:

./srcds_run -game cstrike -secure  +map de_dust2 +ip 65.39.193.213 +port 27016 +maxplayers 40

I start it and connect. I then watch the server's resource usage as a friend frags bots on my other computer. At round start, cpu usage is around 98%. For the first half of the round, it never goes below 65%, peaking at over 95.
At the end of the round when perhaps 1-2 bots are alive, it's at 16-20%.

A perfectly identical srcds runs on the 2x2.66 E6700 / 2GB RAM that I am typing this on perfectly with 34 bots under the exact same OS.

As I type this, the server is running a 34-slot (20 bot) Zombie Riot with Market, Stripper: Source, and SourceMod installed. It is running perfectly fine, even full to the limit. However, the moment I increase the bot count past roughly 24-26, it goes haywire.

Any assistance would be greatly appreciated. Please let me know if there is any more information I might have that could help.

[BehaartesEtwas]

just too much bots? bots are using much cpu, they need to calculate their actions and reactions!

[Appl3]

It's a bit strange considering computers with 1/4 the power can run twice the bots isn't it?

That's my issue here.

[pengy]

I think you changed something in the kernel config that made it do that...

[Appl3]

I changed nothing, everything was freshly installed perhaps a day before with no modifications.

[Appl3]

So no ideas anyone?

Week-bump.

[pengy]

-tickrate 33?

[Appl3]

Tried that at some point and tested, the difference was minimal.

Load issues were the same on 33, 66, and 100-tick settings. Always spiking to absurd levels quickly.

[pengy]

Hmm, older xeons or newer ones

[Appl3]

Perhaps two years old, new at the time.