If you only use the L2 cache (no ram cache), the cache performance shall generally close to the Optane Memory native performance, and in some cases, it even exceeds the Optane Memory itself. We published an article about acceleration experience of using optane memory 16GB as a cache for a HDD or a sata SSD. We also measured its read/write speed. Please see
Optane Memory has much higher read performance than normal SSDs, while its write performance is not good. So Intel launched it for read acceleration to speed up Windows boot and application startup etc. Of course, its write performance still higher than normal HDDs.
For level-2 cache, usually 20GB cache capacity is enough for most Windows and applications and user data. Of course, as others pointed out, it depends on data usage pattern. If there are a large amount of data frequently accessed in daily work, then you may think about a bigger cache to get higher cache hit rate.
Regarding PrimoCache Defer-Write, please note that so far it still has the risk of data loss on power outage, system crash/hang, even you only use the SSD caching.
I remember this bug has already been fixed, though I cannot recall which version fixed it.Jaga wrote:I'm not certain what Romex did to get around issues with the RST driver/software when I reported a fatal bug many years back - perhaps Support can chime in on it.