Thanks everyone, the replies have helped me clarify what I actually want from this machine.

I should have mentioned that it is also my fallback PC in case something happens to my laptop. I used to play older games on it, and I still have some games on physical CDs and DVDs, so keeping the optical drive is useful. Emulation also sounds like a good additional use.

The idea I am leaning towards now is keeping it as an on-demand multipurpose machine rather than trying to make it a 24/7 server.

I would like to use it for:

• learning Linux, Docker, virtual machines and self-hosting
• experimenting with local LLMs and automation
• backing up and synchronising files when the machine is switched on
• older games, physical discs and emulation
• acting as an emergency computer

At first I can experiment with CPU-based local models, even if they are slow. Later, when I can afford it, I may add a second-hand NVIDIA GPU with enough VRAM for local AI. I would probably keep the current CPU initially and replace the motherboard, CPU and RAM as a separate platform upgrade much later, rather than investing heavily in another FX processor.

For the server side, I do not think it makes sense to leave this old FX system running constantly. My current thought is to let it start file synchronisation and backups automatically whenever I turn it on, run any AI or self-hosting experiments I need, and then shut it down again. Maybe I could experiment with sleep and Wake-on-LAN eventually, but I want to keep the first setup simple.

I will also check the exact PSU, motherboard model, temperatures and drive health before buying or relying on anything.

Does this sound like a sensible compromise? I would especially appreciate suggestions for a beginner-friendly Linux and Docker setup that would still let me use the computer as a normal fallback desktop.

Thank you for the detailed reply. It was useful, not rambling.

The distinction you made between actively using an older computer and leaving it idling as a server helped me decide what direction makes sense. This is also my fallback PC, and I still use older games and physical discs, so I think keeping it is more valuable than selling it cheaply.

I am now considering using it as an on-demand AI and self-hosting lab. It could synchronise files and make backups whenever it is switched on, while also running Linux, containers, local models and automation experiments. I would then shut it down when I am finished rather than leaving it online continuously.

I also agree that replacing usable hardware purely for efficiency can be misleading once manufacturing impact is considered. My goal is now to extend its useful life without pretending that an old FX desktop is an efficient 24/7 NAS.

Your point about treating the electricity use as an investment in learning was probably the most useful perspective for me.

I am interested in automation, local AI and self-hosting, so even if this is not an efficient permanent server, it could still be a very useful experimental machine. I think I will keep it off most of the time and switch it on specifically for learning, backups, AI experiments or older games.

I will also look into undervolting once I have checked the exact motherboard and measured how stable the machine is. Thanks for pushing me to think about the value of the skills rather than only the efficiency of the hardware.