Yes they are colored. Two black, two Green.They will work in 2 x dual channel, provided they are set up correctly. Consult your motherboard manual how to place the RAM sticks. The RAM slots are sometimes colorcoded:
https://upload.wikimedia.org/wikipedia/commons/8/82/DDR3_RAM_slots_–_dual_channel-top_oblique_PNr°0302.jpg
These aren't:
https://forums.tweaktown.com/attach...ram-dual-channel-970-extreme3-r2-0-a-dimm-jpg
In the top right however, you can see DDR3_A1, DDR3_A2, DDR3_B1 and DDR3_B2. A1 and B1 go together, just like how A2 and B2 go together. Check your motherboard manual for more, accurate info.
That I know. BTW, what if I ads only one 8gb with 4x2 gb?Then make sure the same sticks are in the same colors. 4GB in green, 8GB in black for instance.
Here is my mother board support lsit for ram. I also mark the ram model with red mark.Only the set of identical sticks will work as dual channel. The 8 GB would be added as standalone. There simply need to be 2 of the same kind to make use of dual channel.