The wee M.2 2242 form factor of the RC100 means there is no space for a DRAM buffer, which led Toshiba to utilize the Host Memory Buffer feature included in NVMe revision 1.2.  In order to use this feature you must be running Windows 10 Fall Creators Update (or 1709) or the at least the 4.14 Linux kernel.  It commandeers a portion of your system RAM to act as the cache, somewhat less effective than having it on board as The Tech Report's testing shows.  As well it is hampered its PCIe 2x interface, which ensures it falls behind 4x NVMe drives. 

The testing reveal the weaknesses of this design, but it is an interesting implementation of an NVMe featuer not often seen, which is in itself worth taking a look at.

"Toshiba's RC100 NVMe SSD takes a bold stab at life without DRAM or a full four lanes of PCIe connectivity. Unlike many DRAM-less SSDs, however, the RC100 has a trick up its sleeve with the NVMe protocol's Host Memory Buffer caching feature. Join us to find out whether NVMe and HMB can bolster this entry-level SSD's performance."

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