<div>
yeah silly me, i realized it in the meantime and installed 64 bit and all ok. thanks!
</div>


yeah silly me, i realized it in the meantime and installed 64 bit and all ok. thanks!

<div>
You have 32bit Windows version and the RAM which exceeds the size of 4GB is useless for you.<br />
You cannot upgrade or update the OS to 64bit which will use entire amount of your 12GB RAM. You need to install from scratch the 64bit Windows.
</div>


You have 32bit Windows version and the RAM which exceeds the size of 4GB is useless for you.
You cannot upgrade or update the OS to 64bit which will use entire amount of your 12GB RAM. You need to install from scratch the 64bit Windows.

<div>
Are you using Non-ECC dual-channel 1333MHz DDR3 SDRAM? &nbsp;And if you are, did you make sure it is properly set in the slots?
</div>


Are you using Non-ECC dual-channel 1333MHz DDR3 SDRAM?  And if you are, did you make sure it is properly set in the slots?

<div>
Thanks, and I was happy to help.
</div>


<div>
<div class="content wysiwyg-content">
I just upgraded the memory for this system. It says 12GB installed (3.17GB usable). In the bios it says 12288MB installed 12176MB available. Any ideas? Maximum memory is not checked in advanced startup. windows 8.1 operating system.
</div>
</div>


I just upgraded the memory for this system. It says 12GB installed (3.17GB usable). In the bios it says 12288MB installed 12176MB available. Any ideas? Maximum memory is not checked in advanced startup. windows 8.1 operating system.

Dell Optiplex 990 12GB memory installed 3Gb usable

A personal computer is a general-purpose computer whose size, capabilities and price make it useful for individuals, and is intended to be operated directly by an end-user with no intervening computer time-sharing models that allowed systems to be used by many people, usually at the same time. Personal computers may be connected to a local area network (LAN), either by a cable or a wireless connection, and through that to the Internet. A personal computer may be a laptop computer or a desktop computer running an operating system such as Windows, Linux or Macintosh OS.

A desktop computer is a personal computer designed for use at a single location due to its size and power requirements, usually by one person. The most common configuration has a case that houses the power supply, motherboard, disk storage (usually one or more hard disk drives and optical disc drives); a keyboard and mouse for input; and computer monitor and printer for output. The case may be oriented horizontally and placed atop a desk or vertically and placed underneath or beside a desk.

Desktops

Components are those devices that are internal to a computer -- the PC boards, the central processor (CPU), the memory (RAM), disk and video controllers and so on.

Components

Since 1984, Dell has been delivering technology to fit your life.
Dell is in Enterprise, Home Office and Consumer sectors of the market, supplying a broad range of customizable desktops, laptops, notebooks, servers, storage, and network devices.