Motherboard compatible with 1 ram but not with two

[Jhonan]

I have a Gigabyte GA-970A-UD3P (rev 2.0) motherboard with a Kingston HyperX FURY 4GB 1600MHz DDR3 CL10 ram installed.

I want to buy a second ram just like the one I have and use them together. I entered that combination in Userbenchmarck.com (just to see the change) but it told me that is compatible with one but not two of the same and and I don't get it at all. (Aparently is a beta function)

Is there a reason for that or there is no problem?

The rest of my components are:
AMD Fx-6300
Nvidia GeForce GTX 950 OC
Seagate 1TB HDD

 

[mbilal2]

Make sure it's exactly the same model, with the same frequency. Follow this link: https://www.gigabyte.com/Motherboard/GA-970A-UD3P-rev-10#support-doc

Click on the memory support list to see if your RAM is listed there.

 

[Jhonan]

It doesn't appear on that list. I saw it was compatible in LogicalIncrements (been using this pc for 8 months) and It's indeed the same ram.

It justseeing the page telling I should not use two rams sticks what confuses me
http://www.userbenchmark.com/PCBuilder/Custom/S39-M299.33835.182068.42917vsS39-M299.33835.412.46543?tab=HDD

 

[mjslakeridge]

That makes no sense. I have a much cheaper, inferior Gigabyte motherboard (760 series chipset) and am using 2 x 4 RAM sticks with no problem.