Beginner Build Feedback/Help

Hello everyone,
I’m new to NAS builds so I apologize if I get anything wrong. I’m looking to build a NAS hopefully using some of the old parts I already have. This build is mostly for Plex and I will try and direct play most content but there might be 2-3 1080p transcodes at one time. I’m unsure which option would be the best and any feedback would be appreciated.

Option 1: Old gaming PC
CPU: Intel Core i5-4670k 4core/4thread
Motherboard: Asus ATX LGA 1150 not sure the model
SSD: 250GB Samsung 850 evo

Option 2: I was given an older xeon and some ram for free
CPU: Intel Xeon E3-1245 V1 4core/8thread
Motherboard: Would need to buy, I was considering a used ASRock B75 Pro3
RAM: 8GB ECC DDR3 (2x4)

Any suggestions or advice would be great!