Question

what is the maximum amount of physical memory

Answer 1

Physical memory of a computer refers to the actual RAM of the system. It is usually in the form of (DIMMs) cards attached to the motherboard. It is also known as primary memory. It is directly accessible to the CPU. It contains the instructions of programs to execute.

Physical memory is the amount of storage on your computer. It is the hard drive space. It determines how many files the computer can hold.

Windows XP Starter has the lowest memory support which is 512MB.

Windows Vista Ultimate has the highest memory support which is 128GB.

All versions of 32-bit Windows including Windows 2000 Professional, Windows Vista, Windows XP support at the most 4GB physical memory.

Upper RAM limits for different editions of Windows 7 are:

Starter - 8GB, Home Basic - 8GB, Home Premium - 16GB, Professional - 192GB, Enterprise - 192GB, Ultimate - 192GB.

Answer 2

The maximum physical memory varies from system  to system and their windows for example window xp support up to 4GB while window 7 strarter maximum physical memory  amount is 8 GB . Also the ultimate version can support up to 192GB. Similarly window vista support up to128 GB.
 Actually the physical memory of the system is the RAM of that system . They are generally directly attached to the motherboard of the system. You can also term the physical memory as the storage present on the system. SO actually it is the amount of maximum files a computer can store or hold.