Doug S (foo.delete@this.bar.bar) on January 30, 2013 12:38 pm wrote:
[snip]
> Another alternative for SoC vendors would be soldering the memory to the board. That would increase memory
> performance, with the tradeoff being inability to upgrade/repair and having to maintain several SKUs (you wouldn't
> need dozens, you'd just offer 3-5 power of two upgrades from very small to very large) Possibly the CPU could
> be soldered as well, though that would multiply the SKUs by the number of speed/core variations.

ISTR reading someone from Facebook mentioning that CPUs have a faster upgrade cycle than DRAM (or the motherboard or I/O chips) and that systems should be designed to exploit different upgrade rates. FRU (or specifically Field Upgradeable Unit) issues might be as significant an issue as SKU diversity.

Having memory and CPU share a board could have energy-efficiency benefits as well as performance (and perhaps reliability) benefits. (A local cluster of such nodes with a shared address space--but not cache coherent--could be interesting for some "cloud" workloads.)