Have you ever been memory constrained do to physical hardware constraints (or budget constraints)? Well Microsoft has decided to help us out a little bit. The addition of the Buffer Pool Extension, adds the ability to extend buffer pool to nonvolatile random access memory for instance an SSD.
This functionality allows the buffer pool manager to use the NAND memory from the Flash Storage to maintain a pool of lukewarm pages (Microsoft term not mine). In effect the buffer pool manager is using the Flash Storage as Level 2 buffer pool that only writes clean pages for safety purposes.
Although the buffer pool extension can be up to 32 times the size of RAM, the recommendation is to maintain a ratio between 1:4 and 1:8. As usual, the optimal ratio can vary, so test as is always the recommendation.
Refer to the following technet article for more information.