Thank you for your replies ! Igor now sounds like Alvin the chipmunk - but he's pretty mean now on fast time controls. The clock does run faster, as expected so I doubled it like you suggest. I played a match with the Saitek Chess Challenger vs Igor and Igor lost although the time was set correctly -

I was wondering if anyone has a list of safe models to tune ( in particular the RS 2200x ) not 2200xl but I heard they are close - same type of crystal ?
How many mhz can it take safely ?

Of course Igor is much more challenging to play and it's hard to move slowly with the clock whizzing away !

many
Thanks,
Queeg