PrimoCache Overview

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. PrimoCache caches data on a logical block basis (offsets within a disk) while windows cache manager caches on a virtual block basis (offsets within a file).

PrimoCache can also utilize the OS Invisible Memory which is wasted on 32-bit Windows when 4GB memory or more is installed.


One of the PrimoCache's core components is a storage class filter driver which resides in the storage stack, intercepting I/O requests for data on disk. If requested data is contained in the cache, this request can be served by simply reading the cache, which is comparably faster. Otherwise the data has to be fetched from disk. Hence, the more requests can be served from the cache the better the overall system performance is.

FancyCache Principle Fig. 1
FancyCache Principle Fig. 2

Main Features

  • Supports LRU (Least Recently Used) and LFU (Least Frequently Used) cache algorithms
  • Supports caching strategies: Read/Write Caching, Read-Only Caching and Write-Only Caching
  • Supports Write-Through and Write-Deferred modes
  • Supports OS Invisible Memory
  • Supports SSD (Solid-state Drive) as Level-II cache
  • Supports persistent caching
  • Supports caching for multiple volumes
  • Supports TRIM command
  • Supports visual performance monitor
  • Supports cache plug and play
  • Supports basic and dynamic disks
  • Supports NTFS junction point
  • Supports volume with proprietary file system

Why PrimoCache?

Why do we need another cache scheme since Windows OS has already implemented a file-system level cache?

  • Some applications bypass the file-system level cache.
  • Windows caches all data, while PrimoCache can cache on behalf of a specified volume in which users are interested. Given same size of system memory, the latter has a higher hit-rate.
  • PrimoCache can utilize the OS Invisible Memory on 32-bit Windows as a cache medium.
  • PrimoCache can utilize SSD (Solid-state Drive) as a cache medium, as ReadyBoost does.


PrimoCache Main UIPrimoCache UI 2

Supported OS

All versions of Windows XP, Windows Vista, Windows 7, Windows 8, Windows 8.1, Windows Server 2003, Windows Server 2008 and Windows Server 2012, including x86 and x64 editions.

More Information

Online Help            Use Cases

Now PrimoCache is under beta testing!

A beta version of PrimoCache is now available for testing. If you have a bit of time, we would very much appreciate it if you could install it, try out the features, and give us any comments you have.

The beta version (90-day testing period) can be downloaded from here

The latest extended trial key file can be obtained from here.

As always, we highly recommend that you test out the beta versions on a non-production machine. We are quite confident that the current build is stable, but it is always best to wait for a final release version. Beta testers should also make sure that they generate backups of the files and databases before testing.