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SpeedGeek · 15 August 2013, 17:23

AFAIK most A4000 owners could overclock to 33 MHz with an A3640 with original IDE PALs installed. But I don't know how many 33 MHz machines were successfully upgraded to PIO2?

You might want to check the speed of your Fast memory and be sure it's at least 70ns (or preferably 60ns) but you can always pull the Fast memory and see if works OK without it.

There should be no problems with Zorro cards since they operate from different or independent clocks from the mobo. I would look for other problems here... low voltage on the +5V supply or bad capacitors on the A3640 or mobo, etc.

15 August 2013, 17:23	#11
SpeedGeek Moderator Join Date: Dec 2010 Location: Wisconsin USA Age: 60 Posts: 842	AFAIK most A4000 owners could overclock to 33 MHz with an A3640 with original IDE PALs installed. But I don't know how many 33 MHz machines were successfully upgraded to PIO2? You might want to check the speed of your Fast memory and be sure it's at least 70ns (or preferably 60ns) but you can always pull the Fast memory and see if works OK without it. There should be no problems with Zorro cards since they operate from different or independent clocks from the mobo. I would look for other problems here... low voltage on the +5V supply or bad capacitors on the A3640 or mobo, etc.