Originally Posted by
Particle
#1 is already known. AMD (in a blog, if I recall) has stated that the interconnect in their MCM product uses an even faster version of the normal HT link used in MP systems. Yes, Istanbul has a snoop filter. What isn't known is how it will apply. Given the extra apparent bandwidth, MC may conceivably not use any filter between the two modules. It would be completely unnecessary for two CPUs in one package just as it is for current 2P systems. (CPU0 goes, "Hey, I don't have that memory address. Since there are only two of us, it must be at CPU1.") I would imagine how that works inside the package will be dictated by how they've rigged up the newly-combined (quad-channel DDR3) memory controller. If each chip in the MCM is set up as one NUMA node, I suspect we'll see the potential for the snoop filter to exist between both dies on the same package when there are 2+ CPUs installed. It makes the most sense though, I think, that they are treated as one. Otherwise it isn't so much "quad-channel" as they've been marketing it as it would be "dual, dual-channel". There's a real difference there.