I have a Dell 11z notebook that runs both Windows 8 Release Preview 32 bit and 64 bit. Originally it was a 2 GB 32 bit Vista, but I upgraded to 4 GB 64 bit Windows 7 without issue for the last 2 1/2 years. The notebook has Intel Celeron 743 @ 1.30 GHz which supports 64 bit architecture.

In Windows 8 64 bit the system recognizes and states 3.9 GB is available. In 32 bit it recognizes only a total of 2.9 GB.

Does the gain of 1 extra GB of RAM available justify using 64 bit?

The net gain is not that great since 64 bit uses more RAM, but it is high enough to reduce overall memory usage by 5 percentage points on average -- (per the memory usage benchmark in the Task Manager).

The reduction in available system memory depends on the configuration of the following:

• The devices that are installed in the computer and the memory that is reserved by those devices
• The ability of the motherboard to handle memory
• The System BIOS version and settings
• Other system settings

For example, if you have a video card that has 256 MB of on-board memory, that memory must be mapped within the first 4 GB of address space. If 4 GB of system memory is already installed, part of that address space must be reserved by the graphics memory mapping. Graphics memory mapping overwrites a part of the system memory. These conditions reduce the total amount of system memory that is available to the operating system.

Method 1: Check the system configuration settings

This problem may occur because the Maximum memory option is selected incorrectly. To fix this, follow these steps:

1. Press Windows + R, type”msconfig” in the Run Window and click on OK.
2. In the System Configuration window, click Advanced options on the Boot tab.
3. Click to clear the Maximum memory check box, and then click OK.
4. Restart the computer.

Method 2: Update the system BIOS

The problem may occur because the system BIOS is outdated. If you have an older computer, the system may be unable to access all the installed RAM. In this case, you have to update the system BIOS to the latest version. For information on updating the BIOS (Basic Input Output System) contact the system manufacturer.

BIOS Disclaimer:
Modifying BIOS/ complementary metal oxide semiconductor (CMOS) settings incorrectly can cause serious problems that may prevent your computer from booting properly. Microsoft cannot guarantee that any problems resulting from the configuring of BIOS/CMOS settings can be solved. Modifications of the settings are at your own risk.