I watched this video and got inspired that this kind of hardware could be used as a LVM cache for m.2 pcie SSD. I believe that this would greatly improved performance even if it's size would be pretty small compared to SSD's size. For today's standards it would need to be pciexpress 3.0 or 4.0 x16 (that would be great amount of bandwidth and much smaller latency compared to SSDs).
Thanks.
31 Answer
Last hardware board for consumers I found was Gigabyte GC-RAMDISK i-RAM circa 2006. These fell out of favor as they require battery backup like array cache modules, and as non-volatile solid state got faster.
Yes, reading a MB from DRAM is about 4 microseconds, faster than 62 us or so from SSD. For in the best case a 15x speed up, are you willing to bet the integrity of your data on the battery backup of your RAM disk?
Actually, it won't be that good, because kernels are not usually optimized for latency that low.
Consider the alternative of having lots of DRAM for volatile memory like usual. The OS can use it for caching. You still could have a LVM cache disk, but maybe just a high endurance, low latency NVMe to eat the writes.
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