There's a difference between overkill and stupid. Why 64GB when you're not even going to use 8GB? It's also DDR4, so it's like almost twice as expensive as DDR3. If you're going to buy 64GB of RAM, you better have a use for it and know for sure that you will use it.
This is what you look like with 64GB of RAM:
You must login or register to view this content.
And something tells me this a prebuilt. A prebuilt with this kind of hardware, you're looking at at least $5k. I would never pay $5k for that build.
i5-4690K / i7-4790K, 8GB / 16GB RAM, GTX 980 TI, build it yourself.