CPU OVERCLOCK: add ultimate option for 2.1 GHz, normal default to 1.9 GHz

Signed-off-by: Paul Reioux <reioux@gmail.com>
GPU Overclock: initial GPU overclocking to 487.5 MHz

Signed-off-by: Paul Reioux <reioux@gmail.com>
GPU Overclocking: add 450 MHz option

Signed-off-by: Paul Reioux <reioux@gmail.com>