Re: AMD dual core vs Intel core 2 quad
On Wed, Feb 06, 2008 at 11:59:14PM -0800, Francesco Pietra wrote:
> Together with other suggestions that were kindly provided, that above makes an
> alluring prospect for me. Thanks. My point of view is that when a 8xxx series
> is offered, they already have a 8xxxx series ready for offer. I rely much on
> the quality of the software, too, in particular the algorithm for
> parallelization and the model, i.e., for MD the force field. Bad ones fight
> against any advancement in hardware. I would be much indebted for a
> clarification of details, at the reader convenience.
>
> ----8xx series (without their box/fan) are found for little. Should the four
> 8xx be the same clock? (as they are found as single, or at most as pairs).
> Also, is the box/fan specific of the 8xx series or can I use the box/fan for
> the 2xx I have? (and only look for two additional boxes/fans).
I believe that they have to be the same speed, and in general it is
recommended that they be the same revision (stepping) as well. If they
have the same code on the box, then they should be good to work
together.
> ----In the European union - where I am - a four-way mainboard for 8xx and 184
> pin ECC is not easy to find. Worldwide, I came across brand new "Supermicro
> H8QCE-B Quad Opteron 800 Dual Server motherboard" and "Supermicro CK804 Quad
> Opteron 800 Dual Server motherboard" at an affordable price (though as much as
> $200 are charged for shipping).
The problem is that the old DDR based systems are obsolete and the DDR2
based ones are the ones currently made. No one wants to stock obsolete
equipment making it hard to find.
> ----As to the mainboard, which specifications should I check in order that
> there is no too narrow bottleneck for the 8xx cpus and ECC 400MHz? Optionally,
> it might help to have a connection to make a cluster with an 8-way server,
> should I decide one day to transfer my private server to my institution.
The standard interconnects on the opteron ought to be plenty to handle
the memory bandwidth.
> ----Can different memory slots (8 2GB ECC and 8 1GB ECC, all 400MHz and same
> voltage) be assembled into the 16 slots of the mainboard?
Yes. Preferably you should balance the ram between the CPUs if
possible, but most important is to make the dual channel work so each
bank has to be matched. If you have 24GB, you could put 6GB per CPU
with 3GB per bank on each CPU.
of course ram is probably (not sure about registered ecc ram) cheap
enough that it really is a rather insignificant part of the cost of a
full system. It may make more sense to go for the new style 8xxx
instead with new ram. DDR2 has more bandwidth than your current ram, so
if your application uses a lot of ram that could make a big difference.
After all if you want 8 cores, that could be done with either 2 opteron
2300 series, or 4 8000 or 8xx series, or 2 8300 series. 4 8300 series
would of course give you 16 cores on a 4 socket board.
Looking at prices I see a quad core opteron 2350 is around $400, while
an 8350 is around $1200. A dual core opteron 870 costs about $600 (so
half the cores of a 2350 at the same clock speed for 50% more money).
So to get 8 cores you could get a dual socket board with two 2350's for
$800 for CPUs, while for an 870 you would need a 4 socket board and
$2400 worth of CPUs. How much ram could you buy for the difference? A
two socket board is likely to be a lot less than a four socket board as
well, and being the new 2xxx series with DDR2 it is likely to be much
easier to find. DDR2 ram also costs less than DDR ram these days. You
can get a dual socket system that holds up to 32GB DDR2 ram with 2xxx
series CPUs for about $400, like for example this one (no idea how good
it is):
http://www.directcanada.com/products/?sku=10530BD5632&vpn=KFN4-DRE&manufacture=ASUS
Basicly it can be VERY expensive to try to reuse old parts.
--
Len Sorensen
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