🚀 go-pugleaf

In article <1992Aug21.094137.23@nsrvan.vanc.wa.us>, I write...

#	I noticed upon opening up my VS3100/30 that the *only* changes between
#it and the 'faster' VS3100/40 are the clock (66.6666 MHz vs 44.4444 MHz) and
#a jumper. This is down to the chip part number.
# 
#	The cost of the 66 MHz osc is about $10 so when I find one I'll give it
#	a try.
# 
#	My questions are:
#	Who has done this?
#	What is the max clock freq that could be used?
#	Do you need additional cooling above 66 MHz?
#	What componet typicaly fails first as you raise the clock?


	So to answer my own questions I did it! First off the results are GOOD.
It works! And at a cost of almost nothing. Now on to the results.

	Clock freq	DR benchmark time	Comments

	44.4444 MHz	3.029 sec		baseline test
	64.0000 MHz	2.130 sec		Yes! did not have a 66.666 osc
	74.3040 MHz	3.112 sec		Boo, memory wait states?

	I used a 64 MHz osc because I had one available. The 74 MHz osc is
the real kicker. I suspect that memory access cannot keep up with the CPU
and has to insert additional wait states. Hey, How about one of you DEC
engineers mailing me a schematic for the VS3100? (Ethan VanMatre 17104 ne 35th
Cir, Vancouver, Wa 98682) 

	Kids don't do this at home, I'm a proffessionnal and of course this will
void your warranty and the like. Be aware there are more than one versions of
the board. 

	I was going to give a description of how to do this but if your willing
to try it you should allready know the precautions and techniques. Just replace
the CPU 44.4444MHz ttl osc with a 66.6666 MHz ttl osc and change the jumper in
the lower lefthand (as you face the front of the unit) from the inside position
to the outside position.

best of luck, Ethan