RAM Speed, Potential Conflict?

[LieutenantDansLegs]

I currently have a 2x4GB (8GB) set of G.Skill Sniper RAM. The speed is clocked at 1866, I just recently purchased another 4GB stick so I can have a total of 12GB of system memory. It is still the Sniper series by G.Skill but I noticed the speed for the single stick is clocked at 1600. Will the slight speed difference cause any performance issues when I add it to my current set up?

Links to the RAM:

Set I own:
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231460

Stick I just purchased:
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231766

System Specs:
Asus Sabertooth Z97 Motherboard LGA1150
Intel i5 4570 3.2GHZ
GTX 970 ssc GPU
8GB G.Skill Sniper RAM
Coolermaster 212 EVO (2, 120mm Fans)
Rosewill HIVE 650watt PSU
Thermaltake MK-1 Chaser (Chassis)

 

[BadActor]

At the very least, your RAM will default to the lowest clock speed of whatever sticks you have installed. Unless you are using every bit of RAM you now have all the time, adding one more stick will not help you because you will lose dual channel. If you need more RAM, you should buy a kit (matched sticks) in whatever capacity you need.