Its not only Japanese games ... its majority of games.I hope I don't offend anyone, but the main advantage of the 3D-VCache is for me to compensate the poor performance of crappy "Japanese" made game engines.
Japanese games aren't really optimized for multi-core performance so, single-core performance is more important.
And if comparing the R9 9900X and R9 9900X3D in japanese games, then I can say that due to the 3D-VCache the R9 9900X3D delivers almost 20% more single-core performance than the R9 9900X in those games...
The more it is important while emulating games where you have every core for performing only one task.
Only handful of games can utilize multicores. So 3D-VCache is acceptable for those hardcore gamers, and single core max speed still valid to this day not only in games but also with LLM`s - as with higher single core threaded cpu you can get higher token/second running interference.
Also, latest R9 9950X3D is a beast in productivity too ( as seen in benchmarks ) shame pricing is a bit Oooof.