Sometimes a server announcement is as defensive as it is offensive. So it is with the UltraViolet Altix UV big bad blades that Silicon Graphics showed off at SC09 in Portland, Oregon, Monday afternoon. Even before it went into bankruptcy for the final time and was eaten by Rackable Systems, which subsequently took the SGI name …
Why would you use a NehalemEX in a 2 x socket blade? Memory bandwidth, OK, but isn't SGI hamstring itself, versus 2 x socket clusters by using a more expensive CPU? The 3Leafs, and ScaleMPs of this world will be happier.
Re: EX in Two Socket config
The article explains the reasoning for the more expensive EX vs. the EP: they needed the extra QPI links to connect to the NUMA widget.
SGI isn't painting itself into any corners here with the EX: they're building an x86 shared memory machine on a scale that makes them unique in the market. The value of a true shared memory machine is compelling for a portion of the systems market. (That's pretty much why SGI was still shipping Itanium Altix. There are very few vendors (IBM, SGI, ?) offering SMP systems with more than a few dozen sockets.) The Nehalem EP would have limited them to one socket per NUMAlink chip. That may have been an unsuitable ratio of $ spent on processing vs. $ spent on the NUMAlink infrastructure. Balance is a big deal in these machines.
I wonder where the pricing will end up? Will they price just under the IBM umbrella and charge a premium? Or will they go after the top end of the cluster market?