Primo Ramdisk Vs. PrimoCache

Primo Ramdisk and PrimoCache are two software programs which both can utilize physical memory to speed up file access and improve overall system performance. However, they are two different types of software, with different application fields and focuses. Compared with the two, they have their own advantages and disadvantages. In addition, they are independent of each other, and you can install both, or just one, as needed.

Primo Ramdisk

Primo Ramdisk is a simulation software program whose core function is to simulate hard disks with memory. The read and write operations on virtual disks are all done in memory, so the read and write speed is very fast. Primo Ramdisk can only operate its virtual disks, and it will not affect, operate or accelerate other hard disks.


  • Faster than PrimoCache, given the same conditions. This is because Primo Ramdisk doesn't involve memory scheduling algorithms which takes up additional processing time.
  • Better targeted than PrimoCache, given the same memory amount. Primo Ramdisk can accelerate only the required files or directories, while PrimoCache targets the entire logical volume.
  • No extra memory overhead.


  • You need to manually configure Windows or individual applications, changing target paths to ramdisks or installing applications on ramdisks, in order to take advantage of ramdisks and achieve the acceleration effect.
  • The capacity of the ramdisk needs to be estimated properly in advance. Otherwise, when the disk is full, new files cannot be written.
  • Data stored in ramdisks will be lost in abnormal situations such as a sudden power failure or a system crash.


PrimoCache is a caching software program whose core function is to use high-speed devices such as memory as a cache to accelerate physical hard drives. It intercepts the read and write requests sent by Windows to the hard disk, and optimizes the processing to achieve the effect of acceleration. For Windows read requests, if the requested data is already in the cache, it can be read directly from the cache without accessing the low-speed hard disk. For Windows write requests, it can first write the requested data to the cache to complete the request, and then slowly write it to the hard disk from the cache in the background.


  • Easy to use and transparent to applications. No need to change existing Windows or applications settings. PrimoCache automatically caches interested data and improves system performance.
  • In addition to memory, you can also use high-speed storage devices such as SSDs to speed up low-speed hard disks.
  • Even if the cache space is full, it will not report an error and stop the read and write requests of Windows to the hard disk. PrimoCache automatically schedules caches according to replacement algorithms, discarding old cached data to cache new data.
  • If Defer-Write is not enabled, there will be no data loss or corruption in abnormal situations such as a sudden power failure or a system crash.


  • Overall performance is not as good as Primo Ramdisk because of extra processing time on memory scheduling. Besides, data stored in the cache might be swapped out when the cache space is full and has to been read from the source disk again on request.
  • No ability to accelerate only certain files or directories, instead of the entire logical volume.
  • Extra memory overhead is required for maintaining the cache indexing 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. PrimoCache is the first choice when ease of use is the primary concern or when the computer does not have enough memory installed. In contrast, Primo Ramdisk is the preferred choice when performance is the primary concern and the system has enough memory installed. The following are the usage scenarios where Primo Ramdisk is preferred, including but not limited to:

  • Used as a download disk for P2P and other download software,
  • Used as as a file sharing disk on a local area network in an enterprise,
  • Used as a turntable or temporary disk for graphics and image processing software,
  • Used as a temporary disk for various applications,
  • Used as a temporary disk for database processing in database servers, .
  • To store static pages of a website in web servers.

Here we give a simple example to illustrate the difference between Primo Ramdisk and PrimoCache in usage scenarios. For example, the goal is to improve the startup speed of  frequently used software. One method is to directly install these software on a ramdisk created by Primo Ramdisk. The ramdisk shall enable the backing image file. When the computer boots up, Primo Ramdisk loads the image file containing these software onto the ramdisk. Thus, these software are ready to run completely in memory, which will show a very fast startup and running speed. Of course, the Windows boot time will be longer because of reading the image file. This method can provide the best performance. However, if you have installed these software on the hard disk and do not want to make changes, or the computer does not have the memory to create a ramdisk large enough to install these software, or you do not want the system boot time affected, then Primo Ramdisk is not suitable and PrimoCache will be a better choice.