In a live memory capture scenario, if the reported RAM is 4GB and the image file is closer to 5GB, what is the reason?

In live memory capture scenarios, the total reported RAM of a device can often differ from the size of the memory image file produced during the capture process. The reported memory, which indicates the total physical memory available for user processes, typically does not account for various other types of memory usage that might not be fully available for direct access by users.

One key reason for this discrepancy is the presence of device cache memory. Cache memory is used by the system to speed up data access for frequently used information, and it can consume a significant amount of RAM. During a live capture, all memory—including the cache—can be included in the image file, leading to a size that exceeds the simple figure provided for user-accessible RAM. This is why the image file size might be closer to 5GB, even if only 4GB is reported as the accessible memory.

Understanding this aspect of memory capture is crucial for forensic analysts and investigators because it informs them about the extent of data that can be retrieved and analyzed, particularly when assessing what has been included in the memory dump they are working with.