How much power does a simple Minecraft server need?

I still have an old office PC standing around at home with an old Core 2 Duo e7500 (2 cores with 2.93 GHz) and 4GB RAM. It would be cool if you could use him for anything else.

Can you make a simple Minecraft server out of it, on which around 5 players can play? Or is a Core 2 Duo too weak for this because the processor architecture is outdated?

Basically it is not a problem to build a server out of your PC. But. There's no relation to the power consumption. The PC will probably be a little too weak to play everything smoothly and converting the PC to a server is actually a little time consuming. The internet speed must also be sufficient for latency-free play to be possible.

That's enough for Minecraft. But if you then have 100 sheep on a chunk, it will of course be tight.

I think it would be enough for a start. Power consumption would not be so optimal, but it would work.