Thanks; I've taken a look; Xi looks promising. Boxx and Polywell look good
but are definitely aiming machines at the graphics market... $400+ video
cards are tough to justify for software development work.
AMD does list a few other vendors on their website. If you click
through to Processors -> Opteron -> Where To Buy, or something like
that, you should be able to get a list of a 20+ on-line vendors
carrying Opteron workstations. Presumably at least ONE of them will
sell decent development systems! :>
Grrr. I'd been afraid of that.
As mentioned bellow, that problem SHOULD be fixed in about 2 months
time. At that time it should be normal to start seeing Athlon64
systems with 4 DIMM sockets. Unfortunately you've only got 4 sockets,
which from the sounds of things might still be a bit tight for your
needs (current 2 x 1GB DIMMs are cheaper than 1 x 2GB DIMMs,
especially if you can use unbuffered DIMMs).
The Opteron 146 is looking promising for that; the 64FX and the 148 are too
pricey for development boxes.
Related to that, for a dual Opteron system, some of them have DIMM slots
associated with a specific processor. If so, I'm guessing that if run as a
single, than only one of the sets of slots will be operable...?
That is correct. The memory controller is on the processor, so if the
processor isn't there, the memory just won't work.
If that's correct, is there some way other than digging through the
documentation of the specific server/motherboard to tell if you can use all
of the DIMM slots with only one processor in?
Not really, though it's usually fairly obvious by simply looking at
the motherboard. For example, take a look at the following boards:
http://www.msi.com.tw/program/products/server/svr/pro_svr_detail.php?UID=484
http://www.tyan.com/products/html/thunderk8w.html
The first board (MSI K8T Master) has all 4 of it's DIMMs connected to
a single processor. As you can see, the DIMMs are all bundled
together right next to one chip. The fact that the same board is
available without a second processor socket just further goes to point
out that ONLY the top processor connects to memory.
The second board (Tyan K8W) has DIMMs attached to BOTH processors. If
you want to use the memory sockets that run beside the AGP slot, you
need a processor in the top socket. If you want to use the memory
sockets in the bottom right of the board, you need a processor in the
bottom socket.
This sort of separate of memory sockets for different processors is
pretty much standard for all dual-Opteron boards like this. If the
memory just connects to one processor, the memory sockets are all
together. If the memory connects to both processors, there will be
two different sets of memory sockets. There is a potential
performance benefit to the latter design (memory connected to both
processors) since you theoretically have twice as much memory
bandwidth. Unfortunately this performance benefit is somewhat
dependant on the operating system having some NUMA optimizations, so
you might not see a noticeable difference.
