Re: What's Old is New Again
OMI is about buffering to allow longer paths between the CPU and RAM and allowing more RAM chips per memory bus (i.e. greater electrical load). Rambus was about decreasing the memory bus width in exchange for very high transfer speeds.
The ideas behind OMI are not new (it has been used in many forms over the years to provide high memory capacities) but it has always had the significant drawbacks of being expensive and increasing latency. Given the latest POWER chips focus on improved IO/memory bandwidth, the drawbacks are outweighed by the benefit of cost effectively increasing memory bus width for large capacity servers.
OMI's advantage over some of the previous methods of increasing memory/memory bus width appears t be around the effect on latency, although I suspect the latency hit maybe compared to other POWER memory options such as Chipkill that already have additional overhead.
Biting the hand that feeds IT
