Where did my 4 GB of RAM go?

08.14.2009 08:29 PM Comment(s) By Jeff

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.
  • 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.
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.  
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