Windows detects 2.75 GB or no more than 4 GB of memory
Often after installing more than 2 GB, users may notice not all of the memory is detected. The total memory supported by any 32-bit edition of Microsoft Windows is 4 GB.
Users who want more than 4 GB of total memory support in their computer must be running a computer with a 64-bit processor and operating system. Below is a listing of 64-bit memory limitations.
Your motherboard must also support more than 4 GB of memory.
|64-bit OS||Total memory|
|Windows 7 Ultimate/Enterprise/Professional||192 GB|
|Windows 7 Home Premium||19 GB|
|Windows 7 Home Basic||8 GB|
|Windows 7 Starter||2 GB|
|Windows Vista Ultimate/Enterprise/business||128 GB|
|Windows Vista Home Premium||16 GB|
|Windows Vista Home Basic||8 GB|
|Windows XP 64-bit||128 GB|
Why does BIOS detect more memory than Windows?
Some users may notice when they enter the BIOS/CMOS setup that their computer is detecting more memory in it than in Windows. BIOS relies on different drivers than those loaded by Windows, so this is not uncommon.