Using the popular CrystalDiskMark benchmarking suite, Twitter/X user @GPUsAreMagic posted a result showcasing some pretty incredible results - a read speed of 182 GB/s and a write speed of 175 GB/s. You might think this was either fake or the app glitching, but with the tag CrystalCacheMark, the result comes from using the 32MB of 3D V-Cache on the Ryzen 7 5800X3D CPU as a RAM disk.
Sure, with a capacity of 32MB (out of a total of 96MB of V-Cache on the 5800X3D), you're not talking about much in the way of storage, but 182 GB/s is the sort of read speed that makes the latest SSDs look like floppy disks from the 1980s. We're blown away by PCIe Gen 5 drives hitting 12GB/s, so seeing 182GB/s is insane.
Setting up and using the CPU's limited 3D V-Cache as a storage device requires an OSFMount tool, which allows RAM disks to mount image files in various formats. Not only that, but precise CrystalDiskMark settings needed to be used.
Those settings include using a specific SEQ 256KB test with a queue depth 1 with 16 threads. Again, with 32MB being used, it's far from practical, but using L3 Cache as RAM disk storage isn't that far-fetched. That is if you've got piles of Scrooge McDuck-like money sitting around. AMD's super high-end EPYC Genoa-X processors pack over 1GB of L3 Cache, which is enough storage to be considered workable.
Setting up dedicated RAM disks has become a thing of the past thanks to the arrival of fast SSDs, so it's great to see the technology being put to great use - even if it's more 'interesting' than anything else.