@TNA
Well I mean NVcache never actually existed other than as a rumour from MLID who is the source all others quoted. Whether he made it up or does have a source who told him something is up for debate! Some seemed to infer a HBCC equivalence but quoting from mlid’s video he doesn’t say it works like HBCC, he says it’s Nvidia's
answer to HBCC:
RTX IO leverages your SSD for enhanced load times and more efficient VRAM usage... it’s more or less what he said (not sure there’s any ddr component, but they describe it as a “suite” so potentially there are details to learn yet as to how it works in reality outside of a very high level overview we got).
And yes, it does appear to be their implementation of MS’ direct storage API... although conceptually closer to MS’ whole “velocity architecture” imo than just the direct storage API as it also features the hardware accelerated decompression which is an important factor in its potential usefulness. Overall it fits the “NVcache” rumour pretty well, albeit by a different name. So that’s the answer to your question of what happened to it.