>It would seem that rationalization would fall apart quickly with the new Power CPUs that have NVLink
NVLink has 80GB/s [1]. DDR4 quad channel (Xeon Servers) has ~120GB/s [2]. So no this rationalization doesn't fall apart. Furthermore in the event NVLink gets faster then RAM, then you'll still be bottlenecked by RAM access, as you'll buffer here.
This of course is ignoring weird systems where you attempt to maintain ACID coherence of tables between GPU, CPU, and Disk memory. But then GPU memory size become inherently limiting as even the biggest max out at ~32GB.
NVLink has 80GB/s [1]. DDR4 quad channel (Xeon Servers) has ~120GB/s [2]. So no this rationalization doesn't fall apart. Furthermore in the event NVLink gets faster then RAM, then you'll still be bottlenecked by RAM access, as you'll buffer here.
This of course is ignoring weird systems where you attempt to maintain ACID coherence of tables between GPU, CPU, and Disk memory. But then GPU memory size become inherently limiting as even the biggest max out at ~32GB.
[1] https://en.wikipedia.org/wiki/NVLink
[2] http://www.corsair.com/en-us/blog/2014/september/ddr3_vs_ddr... (2channel -> 4channel x2)