Even the fastest of the fast SSD's (PCIe based / RAID 0 setups / NVMe / M.2 or similar type drives) are still too slow to be used as system memory.
I've got an M.2 RAID 0 setup (dual 512 MB Crucial M.2 SSD's) on this machine, and while it screams holy terror speed wise, it's still nowhere even close to being usable as RAM, sadly.
