I have a toshiba satellite L455D-S5976 and it is 2 gb ddr2. Ok, I have installed it a 4 gb ddr2 ram but, when I check the system info it says: Memory: 2.8 GiB. I don't know if that number is refering to the RAM quantity, but I want to know if I have done rigth the process? I can use my computer normally, but I don't know either if it have to make something different or be more fast, dunno.

Any answers are welcome.


If your Ubuntu installation is 32-bit, then it will only see 3 GB RAM, and the 2.8 total you're seeing sounds about right (the remaining 200MB are probably reserved by the kernel).

For your system to fully utilize the extra RAM, you have two options:

  1. Installing 64-bit Ubuntu.

  2. Less intrusively, you can install the PAE kernel. In a terminal type:

    sudo apt-get install linux-generic-pae

This kernel uses the PAE features of your CPU to address more than 3 GB of RAM even on a 32-bit CPU.

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    The non PAE limit is 4gb, not 3 GB. That is reduced by hardware memory resources like video memory, but that is usually less than, not more than 1 gb. – psusi Jan 26 '12 at 5:06

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