it is a small closet about one square meter large. I forgot computer needs air circulation. So, it is not a good idea.
Take a look at the CPU usage percentage (in taskmanager) and compare the number when your trading program is not running, versus when it is running. How much does the CPU % increase? Has the fan always made those noises during those 3 years? Or is it getting worse over time?
The usage jumped from 2% to 83% when trading starts. And the fan becomes noisier in these years. I just opened the back cover and cleaned the up the dust. But it does not improve much.
You need to open up the whole chassis, and blow out the intakes, the fans themselves, the whole darn thing.
You need compressed air, because the cooling fins will have dust stuck in there which a vacuum cleaner cannot get to. Trust me on that.
Is mini-PC good? There is a bunch of Mini-PCs on Amazon. Some of those have the com port. Is that the unnecessary cost?
For goodness sake, go get an extra-long HDMI/DP cables, an extra-long USB cables with connectors, an extra-long power supply cables, an extra-long LAN cable and put the PC very very very far away. Alternatively, get a very powerless laptop that is noiseless. I have learned to live with my very loud CPU/casing/graphic cards fans noise from my powerful gaming PC. so I don't have to get those extra-long cables with connectors.