I have a Ubuntu Server installation on VirtualBox since I am a Mac OS X user and I want to launch some Linux-dependent programs on Ubuntu rarely by connecting it via SSH. Therefore I want to make a fine tuning to Ubuntu installation (not as much as changing the kernel) to consume less system resources.
On the idle state (no ssh clients connected, no intentional user programs running) it consumes about %2-2.5 CPU and 450 MB of RAM.
I'm looking for ways to decrease this. Main purpose is to develop some C programs using vim and gcc.