Installed 2X8gb sticks of RAM. CPU-Z shows 16gb, but BIOS/Windows shows and uses only 8gb

[Floormonitor]

I'm very, very, very new to computers. I just bought a custom built PC for cheap off of a friend. I'm trying to upgrade it myself. Here's what I have:

The mother board I'm using is AsusTek P6X58D-E with Intel X58 chipset, DDR3 RAM, i7 950 processor, Nvidia GeForce GTX 570 graphics.

It has 6 dimm slots (and max 24 gig ram), and Windows 7 64-bit. It originally had 3 2gb sticks in it, I added 2 8gig sticks. I checked compatibility with the motherboard and it should support this RAM http://item2.gmarket.co.kr/English/detailview/item.aspx?goodscode=718633075 (I live in Korea now so I had to buy the ram through this site).

I have the RAM in the right configuration, however I don't think it's a DIMM slot issue because my previous 3 stick setup worked in those slots, as well as CPU-Z recognizing both sticks.

I have most of the settings for voltage and timings in BIOS set to auto.

I also noticed that with the new RAM set-up that my computer starts like a lawnmower. It'll turn on, turn off, turn on again, turn off, then start normally.

My computer also works fine when I put in my old 3X2gb configuration.

Again, I'm really new with computers so I'm not too familiar with most jargon. Any help will be greatly appreciated. I would like to trouble shoot the sticks I bought as much as possible, it was difficult for me to buy them in a foreign country, and will be even more difficult to return them.

 

[Tradesman1]

The mobo is made to use up to 4GB sticks, not 8GB, it supports up to 24GB total in a 6x4GB config, the system 'sees' you DRAM and try's to use it, but can't. Best to get a package of 3x4GB or 6x4GB of DRAM that is actually compatible

 

[Martell1977]

The x58 platform is "triple Channel" and so for best performance you want to run 3 RAM modules. I have 3x4gb. The motherboard supports up to 24gb of RAM, so I cannot use bigger than a 4gb module in each slot. (4 x 6 = 24)

 

[Floormonitor]

Thanks guys for the input, I just got my 3x4gb sticks in today and it works like a charm! The computer doesn't start like a lawnmower anymore, and I can finally explore the Commonwealth in Fallout 4 without low memory warnings!