Gigabyte GA-Z68AP-D3 dual channel memory issue

[BrutalDlux]

Hi, apologies if this is a dumb question.
I'm having some trouble with dual channel RAM, i have 2x 4GB RAM (2x2GB), but with both stick in i only get 4GB in total. If i take one stick out i end up with just 2GB. My credentials:

Gigabyte GA-Z68AP-D3 Motherboard
Intel i5 2500k processor
2x 4GB RAM (2x2GB) Kingston KHX1600C9AD3B1K2/4G
Windows 7 64bit

I understand from what i've read that i may need to change some setting in the bios, i'm also concerned that i may have RAM that is not compatible as it shows that it requires 1.65v and my mobo only takes 1.5v.
Any advise you can give would be really appreciated.

 

[GhislainG]

Each module in a KHX1600C9AD3B1K2/4G kit is 2GB. You need 4 modules for a total of 8GB.

 

[aqe040466]

Okay so you got 2 GB for each module you wanna make it 8 GB, you should buy 4 modules of 2 GB each.

 

[BrutalDlux]

Oh really?! Damn that was dumb, sorry. A friend gave me the RAM and gave me the impression it was 8GB, a breakdown in communication perhaps. Thanks guys, at least i know now ^^

 

[GhislainG]

4GB of free RAM is nice.