Why is some of my RAM not usuable?

May 31, 2011 9:57 AM

My Windows 7 laptop says "Installed RAM 6.0 GB (2.87 GB usable)." What? Why is some of my RAM not usable? I have a 4-GB stick and a 2-GB stick, but I'm only getting 3 GBs of use of out them?
posted by jackypaper to technology (6 answers total)

Probably because you're not using a 64-bit version of Windows.
posted by kbanas at 9:59 AM on May 31, 2011 [1 favorite]

Are you using a 32-bit version of Windows 7? You need a 64 bit OS... 32-bit Windows will only use 3GB.
posted by robt at 10:00 AM on May 31, 2011

See here:

http://windows.microsoft.com/en-US/windows7/32-bit-and-64-bit-Windows-frequently-asked-questions
posted by kbanas at 10:00 AM on May 31, 2011

Related thread not shown in the "Related questions" at the bottom.

Even if you don't change to 64-bit, you can still use your 3+ GB of RAM as a ramdisk.
posted by Bangaioh at 10:41 AM on May 31, 2011

The above responses are good. Also, it looks like an additional 128 MB of RAM is being reserved for use by your GPU (pretty common, especially on laptops, where the GPU is integrated rather than standalone), hence the 2.87 GB remaining usable.
posted by Nothlit at 10:52 AM on May 31, 2011

The "ram" being used by the video card in that scenario is regardless of whether the ram is shared or not. The limit is in memory addresses, and there needs to be a valid memory address for the video card ram.

I have no idea why it isn't over 3gb. Is it Windows "Starter"?
posted by gjc at 2:37 PM on May 31, 2011