GMOD Server (Linux) taking more then one CPU Core?!

So, basically SRCDS has got Multi-Core Support. GMOD doesnt, or is there anything I need to configure?

I mean, yes it is using all cores. But its never using more then 110% in total, even though it WOULD be required as the server starts to lag with 76 players on (ping 200+). Is there any way to manage this? How do the big US Servers do this with 90 players on it?

Im using Linux Debian 6, starting the server in a screen. And as said, it uses all CPU Core (4-cores). But not more then 110% - even though it could use 400%.

Since Garry licensed the source engine all to himself. (He paid a hefty sum of money to do so) We will have to wait for him to do it on his own. Valve has 0 say over the source engine Garry uses.

Yeah, but why can other Servers have over 80 players? Im sure their screen is using more then 110% of the CPU.

I mean, CS:S has this feature. It is able to use for example 400%. But, I dont get it in gmod. Does anyone know how to fix this issue?