Primo Ramdisk Vs. PrimoCache

Primo Ramdisk and PrimoCache are two software programs which both utilize physical memory to reduce file access time and speed up computers. However, they are two different types of program and have different focuses. They both have pros and cons compared with each other. Besides, they are independent of each other, and you may install one of them, or both, depending on your needs.

Primo Ramdisk

Primo Ramdisk is a simulator program which creates virtual hard disks by using memory. All Windows read and write requests to virtual disks are done in memory without accessing physical disks.

Primo Ramdisk Principle


  • Faster than PrimoCache, given the same target scope. This is because all requests are done in RAM and there is no extra schedule time.
  • Better targeted than PrimoCache, given the same memory amount. Primo Ramdisk is able to target files and folders in which you are interested, while PrimoCache has to target the whole volume.
  • No additional physical memory cost.


  • Changes on Windows or applications are required in order to take advantage of created ramdisks. For example, you have to change the "Temporary Internet Files" location in IE over to your ramdisk for storing temporary Internet files on the ramdisk.
  • Ramdisk size has to be estimated before creation to ensure that ramdisk is large enough for storing. Otherwise a "Disk Full" error will happen when ramdisk is full.
  • Data stored in ramdisks will be lost on system crash, power outage, or other similar situations.


PrimoCache is a cache software program which creates an additional filter layer onto disk storage layer and intercepts Windows read and write requests to disk. If disk data being requested already exists in the cache, PrimoCache serves the request by simply reading its cache. Otherwise PrimoCache fetches data from the disk and store it into the cache, then completes the request.

PrimoCache Principle


  • Easy to use and transparent to applications. No changes on Windows or applications are required. Once cache is created, PrimoCache automatically caches interested data and improves system performance.
  • No error will happen when cache is full. PrimoCache automatically replaces old cache data by new data, and Windows read and write requests will not be affected at all.
  • No data loss or corruption (if Defer-Write is not set) on abnormal situations such as system crash and power outage. This is because data in cache is only a copy of source disk and it still can be obtained from disk.


  • Performance is not good as Primo Ramdisk because of extra cache schedule time. Another reason is that data stored in cache might have been swapped out when cache is full and has to been read from source disk again on request.
  • No ability to target only certain files or folders instead of the whole volume. Created cache applies to the entire volume.
  • Additional RAM cost is needed because PrimoCache has to maintain its cache content information.

Usage Scenarios

As per the summary of pros and cons above, Primo Ramdisk and PrimoCache have different usage focuses. In general, because PrimoCache is transparent to applications and there is no limit on memory amount, PrimoCache is able to work in most scenarios. Usually it is preferred in scenarios where handiness and simplicity is a prime consideration or system does not have enough memory. In contrast, Primo Ramdisk is preferred in scenarios where performance is the main focus and system has enough memory. These scenarios include but not limited to:

  • Using ramdisks as download disks for p2p software to store internet downloaded files,
  • Using ramdisks as share disks to share files in a company,
  • Using ramdisks as video-editing scratch disks,
  • Using ramdisks for static web server,
  • Using ramdisks to store temporary files for many applications.

Let's take a look at an example scenario that will tell the usage difference between Primo Ramdisk and PrimoCache. In this example, the goal is to improve the running speed of frequently used applications. One way to achieve this goal is to install these applications on a ramdisk which enables the image file feature. During computer boots-up, ramdisk loads the image file which contains installed application files to the memory. Thus these applications are ready to run completely in memory, which will show a very fast startup and running speed. Though this way will increase the computer boot time, it is worth. This is because Primo Ramdisk loads the image file with large sequential read. Considering that large sequential read is much faster than random small read, the image file load time is much less than the total time taken to read out all applications one by one. Besides, computer boot time is not a consideration in some scenarios.

The way described above is able to get the best performance. However, it is not suitable if you have already installed these applications on physical disks and wouldn't like to change, or if system does not have enough memory to store all application files. In such situations, PrimoCache becomes a better choice.