Why is it that my PC does not recognize more than 4 GB of memory?
I hope your math isn’t rusty.
Slots. Lots of slots.
Think of your computer’s memory as a bunch of slots. Your computer “remembers” things by placing them into these slots. Due to its design, a computer can only keep track of a certain amount of slots.
Have you ever heard of Windows being referred to as a “32-bit operating system”? A 32-bit operating system, be it Windows or any other product, is only capable of addressing 232 memory addresses (that’s 2 to the 32nd power). Going back to our slots analogy, 232 slots, the most a 32 bit computer can keep track of, works out to 4 GB of physical memory.
How do you get more memory?
32 bits refers to the size of the largest address which the computer is capable of processing. Trying to fit a 64 bit address into a 32 bit space is like jamming the square peg into the round hole. In order to address more memory, you need a computer with a larger address space.
As of this writing, hardware makers are taking advantage of the thirst for more memory by selling 64-bit systems. One such hardware manufacturer is Apple, whose 64-bit Mac Pro is expandable to 32 GB of memory.
One last thing
This is of course a simplified explanation of memory addressing. There are some software solutions that have been implemented in order to address a larger address space within a 32-bit system (such as Windows’ Physical Address Expansion), but they are beyond the scope of this article. If you wish to learn more about software solutions that allow expansion beyond 4GB of memory on a 32 bit system, I suggest you start with this helpful (Windows-centric) article on the topic.
