Hi, I currently have an ASRock 970 Extreme 3 R2.0 and an AMD FX 6300. I am soon going to upgrade to either an ASUS Z170-P D3 which can use my current DDR3 RAM(Corsair Vengeance 1600MHz) and an Intel Core i5 6600k or an ASUS Z170-P which supports DDR4 RAM and an Intel Core i5 6600k. The motherboard that uses DDR3 RAM would be much cheaper, but the DDR4 one would be a very nice upgrade but more expensive. If I were to get the DDR4 upgrade along with the ASUS motherboard and the i5 6600k what type of DDR4 RAM should I get? I would like 8GB to start out and I will upgrade later. I also don't want it to be overly expensive, but also have good performance. Thanks, and any suggestions and responses are much appreciated.