16GB ram installed, 3.5GB usable

[dolfan55aj]

Hello,

Here's my build:
CPU: AMD FX-8150 3.6GHz 8-Core Processor
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler
Motherboard: Gigabyte GA-970A-UD3 ATX AM3+ Motherboard
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory
Storage: Western Digital Caviar Black 1TB 3.5" 7200RPM Internal Hard Drive
Video Card: XFX Radeon HD 7850 2GB Video Card
Power Supply: Rosewill Green 630W 80 PLUS Certified ATX12V / EPS12V Power Supply

Here's my problem:
This is a brand new build, and I have had some trouble getting my computer to recognize my RAM as usable. I installed Windows on 1 stick of 4gb ram (type shown above) because I was having some problems installing with all of them for some reason. So now I'm adding the remaining sticks of 4gb ram (16 total). For each stick Windows recognizes that it has been installed, but I still only have 3.5gb of usable memory. The BIOS shows that the 16gb has been installed as well.

What could be the reason that I'm not getting the rest of my RAM to be usable? I've searched around for answers, but most people say that it's a Windows limitation or a motherboard compatibility problem, etc. I have Windows Ultimate so I should be able to get 16gb and 8gb of the G.Skill ram came with the board, I just ordered 8gb more of the exact same kind.

Any thoughts? First time poster, any help would be greatly appreciated! Thanks!

 

[chugot9218]

Is it 32-bit windows ultimate?

 

[phil22]

You didn't say whether 32-bit or 64-bit Windows.

If it's 32-bit, that's the reason for your problem. It can only address a maximum of between 3 - 3.5GB RAM. Anything in excess of that is ignored by Windows.

You need 64-bit Windows to address more than that amount of RAM.

 

[gelliott]

It sounds to me like you may have installed 32 bit Windows?

Edit: we all had the same idea at the same time haha.

 

[anoldnewb]

What version of Windows are you running? You need to run a 64 bit version of the OS to use much more than 3.5 GB.

 

[dolfan55aj]

Oh my goodness... *facepalm* That was the issue, downloaded the wrong iso to do my Windows install. This explains a lot.

Thanks all for your timely response!

 

[dolfan55aj]

Best answer selected by dolfan55aj.

 

[phil22]

Downloading an ISO? A legal ISO I trust?

 

[chugot9218]

Hah, I was going to comment on that as well...