[SunRescue] Ultrasparc CPU dismantling

[James Lockwood]

On Mon, 1 Nov 1999, Chris Kozlowski wrote:

> Okay, here's the story on the UltraSPARC IIi processors.
> Apparently, the speed of the processor is controlled by
> the little module board, and the rated speed is ignored
> by an Ultra 5.  It is easy to swap CPUs between boards.
> The speed of the CPU moves with the board.  Which leads
> me to an interesting question -- the boards are relatively
> simple, and it is possible that mere resistors are indicating
> to the Darwin at what speed it is to run -- how would we
> modify them to overclock our CPUs?  The 333 mhz CPU that
> I took apart actually held a 360 mhz rated UltraSPARC...

I highly recommend reading the publically available UltraSPARC manuals.
These detail how the processor seeks its correct speed during boot.

All UltraSPARCs have programmable clock oscillators.  The strapping
resistors indicate the default speed that the CPU should run at, not the
only speed.

-James