O&O CleverCache is described as 'optimizes your file cache management in Windows. This results in an enormous performance' and is an app in the OS & Utilities category. There are four alternatives to O&O CleverCache for Windows. The best alternative is PrimoCache. It's not free, so if you're looking for a free alternative, you could try ReadyBoost. Other great apps like O&O CleverCache are eBoostr (Paid) and FuzeDrive (formerly StoreMI) (Paid).
PrimoCache is a supplementary software caching scheme that cooperates with system memory to provide data caching for disks. It improves system performance by transparently storing data into memory such that future requests for that data can be served faster.
Enmotus FuzeDrive (formerly developed by and bundled with AMD hardware) is a storage solution aimed at enhancing the performance of slower physical harddisks (and SATA SSDs) by combining them with faster (NVMe) SSDs and RAM.