785 upgrade info

[Kevin Carosso]

Anyone considering a 785 upgrade should trade in your old memory
controllers and 1/4 meg boards for the new 1 meg boards.   DEC
gave us two reasons for this.  First of all they indicated that
the new boards would give a slight performance improvement over
the old ones (anyone know why this might be?) and every little bit
would help get the most out of the 785.  More importantly, they
strongly suggested that 785's be configured with 12 meg, which
is impossible with the old controllers.

>From experience, the 12 meg sounds reasonable to me.  I know
my 780 uses nearly all 8 meg when loaded (under VMS with big
jobs) and it seems reasonable that 50% more processor could
use 50% more memory.  Also, I know that I have a LOT more trouble
with memory errors on my system with 8 meg worth of 1/4 meg
boards than my other system with 8 meg of 1 meg boards.

	/Kevin Carosso    {ihnp4, allegra, seismo}!scgvaxd!kvc
	 Hughes Aircraft Co.