Without it kinda all scripts use 1gb ram after hours off botting. if u do -mem 256 it will stay 350/450. Dont use WebWalking to ur scripts. But yeah about the CPU it dosent really matter if it runs on 90-95% if u get profit :P
But try with this it should help (Allot)... Helped me to run 100 more bots on each server i got.
-jar OSBot.jar -login username:password -world 383 -bot bot_name:bot_pass:bot_pin -mem 256 -script testScript.jar -allow lowcpu,lowresource,nointerface