On Mon, 26 Aug 2002 11:22:13 +0100
Richard Earnshaw <rearnsha@buzzard.freeserve.co.uk> wrote:

> > Hi,
> > 
> > Not sure if others were already aware of this tweak, but in the BIOS/cyclone of your cats box there's an option called fclk.  It seems that fclk controls the clock for the footbridge.  This clock also drives the clock speed for the memory.  by doing:
> > set fclk 66
> > in the bios I got a 32% increase in memory bandwidth.  From what I can tell the bios defaults to 50MHz.
> > 
> > Obviously you need PC66 DIMMs.
> > 
> > Just thought I'd share this little gem.
> > 
> > Chris
> > 
> 
> I remember playing with this switch only to find that it doesn't do 
> anything useful.  However it does
> 
> 1) Mess up serial lines
> 2) Make "sleep 30" take about 40 seconds

Hmmm, you're right this is way out, going to try different jumpers settings, it could be that the value it being passed wrongly, or the timer setup is wrong.

> All of the above are consistent with the fclk environment variable in the 
> bios being just a constant that is passed at boot time.  To really change 
> your fclk I think you have to flip a switch on the motherboard.

yes, mine was in theory already set to 66....

Chris