Wanted: Good mobo for Intel 850E chipset and 1066 RDRAM

[Camm Maguire]

Greetings, all, and many thanks for your helpful replies.

OK, we're thinking about the Asus P4T533 motherboards with 1066 RAMBUS
memory.  This is a 16-node cluster upgrade.  Our old network was
dual-channel-bonded 100Mbit switched ethernet.  In general, we leave
the network unsaturated by a fair margin on our critical code, but do
find that the network is a slight bottleneck on small problems.

We're considering a gigabit network upgrade, probably using the Intel
PRO/1000T adapters together with the driver in the latest 2.4.20-pre
kernel.  Unfortunately, the Asus motherboards only have 32bit/33Mhz
PCI slots.  As best as we can figure, this will shave a factor of 2
off of the peak possible network throughput otherwise attainable.
Which means that we could expect a rough factor of 2 remaining in
throughput over our existing setup, with no improvement in latency.

The nodes are going from PIII 850Mhz with SDRAM to P4 2.53 and
RAMBUS.  As far as we can tell, this amounts to a factor of 6 for cpu
intensive work (taking into account the extra factor of 2 provided by
the SSE2 instructions), and something less but still high on
memory-bottleneck problems.  So the capability of the machine is being
tilted further in the node capacity direction relative to the network
capacity. 

We're trying to decide if we should take a 30% hit on memory speed in
exchange for a factor of 2 in network throughput by going to RAMBUS
PC800 motherboards with a faster PCI slot.  Of course, if anyone knows
of a motherboard supporting both RAMBUS 1066 and either 64bit PCI or
66Mhz PCI, that would be ideal, but such animals apparently do not yet
exist.

Any advice, suggestions, or commentary are most appreciated.

Take care,

P.S.  We're looking at the Netgear GS516T gigabit switch.  So far
we've been unable to discern whether this switch supports 'jumbo
frames' or whether such settings are even necessary with the Intel
cards.  Any illumination here would be appreciated as well!


Josip Loncaric <josip at icase.edu> writes:

> I forgot to mention one more thing: high speed memory like PC1066 tends to run
> hot.  Users suggest to have good airflow over the memory modules (e.g., keep
> wiring out of the way).
> 
> Sincerely,
> Josip
> 
> -- 
> Dr. Josip Loncaric, Research Fellow               mailto:josip at icase.edu
> ICASE, Mail Stop 132C           PGP key at http://www.icase.edu./~josip/
> NASA Langley Research Center             mailto:j.loncaric at larc.nasa.gov
> Hampton, VA 23681-2199, USA    Tel. +1 757 864-2192  Fax +1 757 864-6134
> 
> 

-- 
Camm Maguire			     			camm at enhanced.com
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"The earth is but one country, and mankind its citizens."  --  Baha'u'llah