RAM disk is a technology that allows a computer’s working memory to be used as a storage medium. This has the advantage of faster speeds than the average hard disk or even ssd, but can also have incredibly low latency. However since the advent of pcie ssd’s, the technology offers fewer major advantages than before. However, the disadvantages are the same as before; RAM memory is more expensive, more limited in quantity, and is volatile.
Now, however, an interesting picture has surfaced from CrystalDiskMark in which a sequential read speed of a whopping 182 GB/s and write speed of 175 GB/s was achieved. This appears to be a RAM disk running on the 3D V-Cache of a Ryzen 7 5800X3D. Achieving this does require very specific settings and the use of OSFMount with which to create the RAM disk. The test values must be set to SEQ 256KB, queue depth to 1 and threads to 16. Also, the data fill must be set to zeroes instead of random. Even with this preparation, good results are not guaranteed because the system also uses the L3 cache in the background, which can affect results considerably.
There does not seem to be any practical benefits to this use of AMD’s 3D V-Cache and the values achieved are not even close to the actual bandwidth of the 3D V-Cache, as it is 2 TB/s for the Ryzen 5000 series and even 2.5 TB/s for the Ryzen 7000 series. Possibly there is still something of value to be gained from applying L3 cache as RAM disk for AMD EPYC processors, as these have 1.3 GB of L3 Cache, which could make any RAM disk a bit more interesting.