Usable RAM vs Installed RAM

Duob

Prominent
Jul 17, 2017
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I recently installed a new gpu and when I wanted to see my system and monitor it, I noticed that I could only use 2.75 GB of RAM instead of 4 GM. My motherboard can support up to 4 GB and I have been using these RAM sticks since I bought the computer as a whole.

What is happening to my RAM, when I cannot access it fully? I have windows 7 home premium and it is x32 bit, so it should read up to 4 GB.