[Info-vax] rx2660 & 1.6 GHz CPU with 24 MB Cache (Itanium 9050)

[MG]

Op 27-jun-2016 om 12:40 schreef Eberhard Heuser:
> for those who want to use the most powerful Itanium CPU in a rx2660 box
> here's some info:
> Though you'll find that only a 9040 CPU is supported (1.6 GHz 18MB
> Cache), but the more powerful 9050 CPU
> (1.6 GHz 24 MB Cache) runs OK, too (at least with the latest available
> firmware):

Looks good and glad to hear it worked out!  (Especially if you
had to pay a fair amount for these officially 'unsupported'
processors.)

What actually surprised me more, especially because it wasn't
documented too well (apart from being listed as 'compatible'
in one or more upgrade guides), was the fact that the rather
dated rx2620 (then already, now needless to say even more so)
could take dual-core "Montecito" CPUs.  I upgraded my rx2620s
of mine two be equipped with dual dual-core "Montecito" CPUs
which I found in a bargain, all the way in Australia, at the
other side of the world for me, at the time.  (Years ago now.)
It was in fact so affordable, even with the fairly prohibiting
shipping costs it was still easily more than three times as
cheap as what sellers were offering in Europe and North America.
So, I couldn't resist.

I ended up with the same amount of logical CPUs as your
rx2660 has (plus with hyperthreading support), but naturally
with a slower bus and the maximum RAM limit of the zx6000/
rx2600/rx2620 systems (although you could, supposedly, with
rare and very expensive 4-Gbyte DIMMs go higher).  I never
saw any rx2620s on auction sites or anywhere else 'in the
wild'.  (I assume, but maybe wrongly, that it wasn't too
terribly common.)

The heat dissipation from a 'dual dual-core' "Montecito" is
not a laughing matter, however... especially during a warm
summer period.  I also remember I needed a replacement airflow
baffle, different power connector cables and such for the
upgrade to "Montecito" processors.  (Was the rx2660 upgrade
more 'plug-and-play' in that regard?)

Performance-wise, though, in my recollection a faster CPU did
not always make too huge of a difference for me, when running
VMS.  I didn't notice too much of a significant difference in
boot times between my DS10s, rx2600s w/"Madison" or even
rx2620s w/"Montecito" (dual-core)...  I began to notice a more
significant performance boost when I began booting off RAID-0/
striped volumes, like from my DS10s with a hardware RAID SCSI
HBA, 'ironically' also with VMS as a HPIVM guest hosted on a
large VxVM/OnlineJFS striped volume under HP-UX.  That was
when VMS truly began to fly.  (I guess VMS benefits greatly
from both large sequential and maybe also random performance.
But possibly the former, because so much is record/database-
structured.)

  - MG