Console commands not working properly NEED HELP asap.

i create No More Room In Hell server using Centos 6 32bit , but there is srcds command console said unknown command "rate" , i cant change that so my server is so lag when there is 200 zombies even just 1 player inside

i think rate cap is 30000, i must change it to 60000 but how , can anyone help me please

Server OS: CentOS 6 32bit
Processor: Intel Xeon 4 Cores
Ram: 2 GB
Game(s): No More Room In Hell
Admin Mods: Metamod, Sourcemod

here screenshot


here my speedtest