From a tech point of view, Optane is super cool. It's the fastest SSD technology on the market in terms of raw benchmarks and numbers, although there's a hefty premium to pay for that. A 32GB Optane stick is the same price as a decent quality 250GB SSD.
The main advantage of Optane and cache drive setups IMHO is that the PC only shows one drive. For some users who need lots of storage
but don't want to manage two drives (e.g. a boot SSD and mass storage HDD), Optane can provide some value. I'd still recommend a single SSD if it's affordable though.
Another use of Optane (which wasn't available at launch) would be to have a small SSD as the boot drive, and an Optane accelerated HDD for large programs such as games that don't fit on the SSD. By having an Optane accelerated secondary drive, launching programs off that drive could be much faster.
Accelerating Secondary Storage with Intel Optane Memory | PC Perspective
Optane does do a very good job of caching though compared to traditional NAND flash SSD cache drives as Optane drives can run at full performance even when they are at capacity (as is standard practice when using a cache drive).
When compared to just a HDD on it's own, the real-world performance of an Optane accelerated drive is very impressive and in real-world tests performance can be on par with an SSD:
Intel Optane Memory 32GB Review - Faster Than Lightning | Client Performance (including RAID testing!)
That said, I'd still recommend:
- A single SSD if you can afford one of a high enough capacity
- A traditional SSD boot drive and large HDD if you are happy managing data on two drives
- An Optane accelerated HDD only if you really don't want to deal with two drives but still want "ssd like" performance for most tasks
(AMD has their own similar device, StoreMI)
A shame StoreMI isn't as good though. It's quite different than Optane technically as it uses a tiered storage architecture rather than a cache system, which is more akin to how large SAN devices work in the enterprise. More info on how tiered storage works in StoreMI here:
YouTube
Does StoreMI Bring AMD on Par with Intel Optane Memory Caching? | PC Perspective
It also has the same downside as Optane as in that it only works on AMD's X399 or 400 series motherboards. It also has a major disadvantage in that you cannot easily convert an StoreMI enabled drive back to a non-StoreMI drive since it tiers data across the SSD and HDD, instead of just using the SSD as a cache.