By: JeffC | August 14, 2009
If you have upgraded your PC memory to 4 Gigabytes of RAM, you may not see all of it. System Properties may only show 3.0 GB to 3.25 GB of RAM if you are running a 32-bit operating system. Why? Here's as simple an explanation as possible. It can get really technical but most people don't really care.
Windows XP 64-bit, Windows Vista 64-bit, or Windows 7 64-bit can address (or see) 2^64 bytes of memory (a REALLY big number - bigger than our national debt. I think that's why they had to invent 64-bit processors and 64-bit operating systems so the government could spend more money ). The key thing to remember is that you have to have BOTH a PC that is 64-bit and an operating system that supports 64-bit. I hope that helps. If you have questions or clarifications, please comment below.
- Binary math: 2^32 = 4,294,967,296.00 bytes of memory. This is the maximum possible that Windows (32-bit) can see.
- Hide and Seek: The PC hardware reserves some of that memory for itself and hides it from Windows.
- More math: 4 GB of RAM - hidden memory = ~3.2 GB of RAM (your mileage may vary)
- Did I waste my money? All 4 Gigabytes of memory are being used, you just cannot see it.