grr@cbmvax.commodore.com (George Robbins) (01/01/90)
Back when the 5800 was announce there was a fair amount of speculation
about some of the hardware details and how the systems differed from
the VAX 6000 series, beyond the different processors...
1) The 5800 processor is two boards vs. one board for the CVAX processor
boards used in the 6000 series. This means two slots per CPU and
worse, the way be backplane is arranged, some of the rear pins needed
to jumper between the two boards are obstructed by a "spider thing"
that appears connect the "memory" slots to the "CPU" slots.
Unless DEC comes up with a different XMI backplane or makes an
integrated spider/jumper thing, you aren't going to see any 5840's.
2) The BI bus consists of two little BI cages permenantly jumpered
together, in contrast to the 6000-210 that has two separate cages
and needs only to have a pair of DWMBA cards plugged in to get
two BI busses.
If you want to BI busses for better thruput or to meet configuration
rules, you get to pay for an expansion cabinet.
3) DIY benchmarks like a diff that takes about 5 minutes on an unloaded
785 show about 9X over the 785. The sucker does "feel" fast, be we
know how quickly you get used to that. Haven't tried any floating
point or more realistic benchmarks.
--
George Robbins - now working for, uucp: {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing arpa: cbmvax!grr@uunet.uu.net
Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)