They release a new RAM with every release of the new CPU.
A new CPU launch, such as the 3rd Generation Core family (Ivy Bridge), is accompanied by a raft of new motherboards, memory, coolers and systems.
Intel says it has improved the integrated memory controller on Ivy Bridge such that running system memory at 2,400MHz-plus should be achievable on a well-engineered motherboard. Faster memory speeds should correlate to better performance, but such is the efficiency of the CPUs' on-chip cache, composed of a three-tier hierarchy, that super-fast memory speeds don't always show a meaningful jump in benchmark scores.
And say it is optimized for that CPU. Maker that offers only couple of items, would go under soon.
They must compete an that is why so many RAM modules is out there.
as the new Ivy Bridge chips feature integrated graphics that are a step above those present on Sandy Bridge models, and the IGP draws its bandwidth allocation from system memory, chances are that 2,400MHz-rated RAM can make a meaningful contribution when gaming on the IGP.