You need to find your original motherboard specifications and see what is the best memory compatibility for working with your BIOS and the motherboard itself. I have found that although Corsair memory works okay Kingston sometimes is better, FYI.
First I would not have bought memory sticks that had different voltage settings. I would have made sure that the voltage settings were the exactly the same
from the memory I was introducing or replacing. I would stick with the 2.12 volts. The reason why the three sticks are working fine is because the BIOS is lowering
the voltage of all three sticks for compatibility reasons. If the BIOS cannot recognise all 16GB then changing the settings under windows is USELESS!
Keep in mind that some motherboards have a cap
on the amount of memory that can be installed on one motherboard. Although the motherboard may accept 16GB of memory in total, the way
it is introduced to the system will have an effect on how the BIOS will read the memory sticks and calculate the amount of memory. For example, you motherboard may cap, totally
at 16GB but you might want to introduce the total 16 GB as (2) 8GB DDR2 1600 sticks, rather than (4) 4GB DDR2 1600 sticks, for example...
Also, most motherboards will share memory
with your integrated video card, keep this in mind, too.
By the way.....
I looked again and it looks like you are sharing main memory with your video card
If you take your memory 16GB * 1024MB = 16384MB minus
the 12288MB (or 12GB) equals
4096MB or 4GB...
That 4GB looks like BIOS is introducing that memory to your internal video card. In other words, you have an integrated video card that needs 4GB of system memory because it has no video RAM to use so it utilizes the system memory.
Also, on your motherboard is your memory slots different colors? IE - 2x Black and 2x Blue, or whatever? Then try pairing your voltages. Since you have memory that differs only in voltages try pairing the 2.12 voltage sticks together and then the 3.19 voltage sticks together. (I still would not recommend using different voltages but since you already have them it is worth a try since you told us that any three memory sticks will work and be recognised on your MB and in your BIOS.)
Also, I have used ZigZag, but I have found that CPU-Z Validator works a little better. I have Kingston memory in my notebook, for example, but one 2GB-bank is made by Kingston themselves and another (although it is stamped Kingston on the outside) is actually made by Hyundai Electronics.
Again, the easiest way is to find your motherboard documentation and read it to find the best way to introduce how you are going to utilize all of the 16GB of the memory cap for your system. Since you have 4 DDR2 slots does not mean that you need to utilize all
of them. Sometimes utilizing just two of them will be better and produce better results than utilizing all four. (Plus it will determine what your pocket book says buying (2) 8GB DDR2 1600 stick of memory can be more expensive than purchasing (4) 4GB DDR2 1600 memory sticks.)
Hope this helps...