Subject: Re: lessons learned...
To: Herb Peyerl <>
From: Bob Knight <>
List: port-hp300
Date: 03/28/1998 16:28:34
Hi - so if I took a 400t w/a 030 daughterboard, popped a 25 Mhz 040 in it,
I should have also put a 100Mhz crystal in, too?

Thanks for your help...


On Sat, 28 Mar 1998, Herb Peyerl wrote:

> Recently I learned a couple of hp300 lessons.  I thought those of you who
> didn't already know this would be interested:
> a) overclocking an 040 is not necessarily koshure... I had a 425T that I had
> overclocked to a 433T.  It worked fine for the longest time until we tried 
> to install a newer version of perl and the install failed.  Then we noticed
> that 'ps -axwl' was printing out numbers incorrectly. as in "1.B" and "1.;" 
> and so forth.  We bumped the oscillator back down to a 50Mhz oscillator and 
> everything started working again...  So it seems just the FPU was unhappy
> but other than that, everything else had worked for over a year...
> b) when I upgraded lager from an 030 to an 040, I had a 25Mhz 040 so I put a
> 50Mhz oscillator in it... I noticed it wasn't much faster if at all from when
> it was an 030 but what the hell.. it had to be faster right?  anyway, then I
> got a 33Mhz CPU so I put it in and replaced the oscillator with a 66Mhz 
> oscillator but the machine wouldn't come out of reset.  Some of you might
> remember my messages to the list on this subject a long while back... so I
> kept it running with the 50Mhz oscillator... 25Mhz was better than nothing.
> Then I got my paws on some more hp400 gear and needed to put some more ram
> in the machine in (a) so I took apart a 433S and noted the oscillator in it
> was a 133.3333Mhz oscillator... I thought "that's odd, I wonder if it's a
> divide-by-4 on the 'S'... So I ran ufc-crypt on the 425T and ufc-crypt on
> lager and lo-behold, lager performed exactly half as fast as the 425T...
> So, lager had been running at 50/4=12Mhz all this time...
> I just popped the 133Mhz oscillator in it and wow! is it ever fast now!