Windows detects only 4.75GB of 8GB RAM [duplicate]

I have Windows 7 64 bits Home Premium with 2x4GB Ram, but the system shows only 4.75GB available in Windows.

There are tons of questions like this on the internet as well as on this site such as 8.00GB RAM (3.22GB usable) in Windows 7 x64

There are many possible reasons and you need to check each:

1. The most common problem is that memory mapping is disabled. You need to go to BIOS setup and look for memory remapping or something like that and enable it. If nothing is found, update BIOS to the latest version and recheck. If still no entry like that, try the next one.

   See Installed Memory (RAM): 8GB (4GB Useable)

   

2. Go to BIOS setup and try reducing or disabling shared RAM for video card

3. Windows+R > type msconfig and press Enter. In tab Boot open Advanced options and check if Maximum memory is being checked. If true, uncheck it

4. Check if there are any devices taking addresses too much. Disable it or reinstall driver

   Windows only sees 768 MB RAM out of 4 GB

5. Take out the memory modules, swap them or plug them into the other pair of slots (if any). Clean the pins if necessary.

If all the other solutions don't work, you may have no luck.

You can read about the reasons and solutions on MS support and MS technet