If you think that the Hummingbird processor in your Nexus S is a bit slow at 1GHz, maybe you can overclock it, like morfic at XDA has managed to do. He overclocked the Nexus S to 1.2 Ghz and developed a new kernal which allows owners of the Nexus S to add an extra 200 million clock cycles to the processing power.
The only problem is that with this increase in speed, you are going to have some glitches. The increased speed disables the phone’s Bluetooth capabilities for one, but hey you have more power. There’s always a price to pay.