Thanks DT for the info, those are some pretty scarey numbers you pulled up!

The reason I asked was I have a three minute timer using DT_14 interrupts and I also used Steves Pic timer calc but I'm consistantly getting the timer out by about -10 secs using the int_osc at 8MHz.

I'll try an ext_xtal and see if I get the same error, but comparing my error to the numbers you pulled up, mines probabaly due to a coding error. :-)

If I find a difference I'll let you know.

Cheers