Depends on your dataset. Systems like Databases perform much, much better the less you have to touch a storage controller. One of the things that's going into Intel's 2017/2018 platform is the support for 6 channels of memory, and not all of that needs to be DRAM. There's a new standard, NVDIMM, that lets you use non-volatile memory as RAM, and take advantage of its much higher densities. So, if you have things like a database, you can map a much larger dataset into actual memory, instead of needing to just have the indexes in there.
