For a DDR3-era machine, you'd be buying RAM for that on Ebay, not Newegg.
I have an industrial Mini-ITX motherboard of similar vintage that I use with an i5-4570 as my Unraid machine. It doesn't natively support NVMe, but I was able to get a dual-m2 expansion card with its own splitter (no motherboard bifurcation required) and that let me get a pretty modern-feeling setup with nice fast cache disks.
I have an industrial Mini-ITX motherboard of similar vintage that I use with an i5-4570 as my Unraid machine. It doesn't natively support NVMe, but I was able to get a dual-m2 expansion card with its own splitter (no motherboard bifurcation required) and that let me get a pretty modern-feeling setup with nice fast cache disks.