How to Calculate Maximum Available Physical Memory


The amount of physical memory that can be safely allocated to a given product varies from system to system. While all products can manage the maximum limit that the particular Windows operating system platform permits, memory should be reserved for the operating system itself, and for the various processes (services and applications) that will be running. Additionally, when active, each product allocates a small amount of physical memory for overhead.

For systems with relatively small amounts of physical memory, up to 1 GB, the amount of available memory may be in the order of 30 to 50 percent or less. For medium sized systems, 2 GB to 4 GB, 70 percent of the physical memory may be available. On larger systems, above 4GB, 80 to 90 percent or more of physical memory may be available for our products.


Each version of Windows desktops (XP thru 8.1) limits the amount of usable memory even though more maybe physically present in the system. For example, Windows 8 Professional 32-bit running on a machine with 6GB of RAM will recognize only 4 GB. The remainder cannot be accessed by the OS. However SuperSpeed products can acccess the additional RAM via our patent pending "Unmanaged Memory (UM)" functionality. So in this case the extra 2 GB can be accessed and used by SuperCache! UM functionality is also available for 64-bit Windows operating systems.

The maximum amount of available physical memory at any moment cannot be predetermined precisely since it changes even as a system is active. Attempting to allocate the absolute maximum amount may ‘starve’ the system of memory resources, actually reducing its performance, and, in extreme conditions, could lead to a system crash.

Installed RAM

Percent Available

Examples of installed RAM on Systems Approximate amount RAM available to SuperSpeed products
512 MB to 2 GB 60 - 70% 512 MB 300 MB +/-
1 GB 640 MB +/-
2 GB 1.5 GB +/-
2 - 4 GB 80 - 90% 4 GB 3.2 GB +/-
>4 GB 95% 512 GB 490 GB +/-

Last updated: 4 June 2014

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