Brief backstory, I bought my desktop PC from PB Tech (custom made) in around March 2018. Ran without any issues but I noticed recently that the internal temperature was slowly crawling up, using the Speedfan app.

When I first got it, anywhere from 20°C-25°C was pretty normal; on cold days, it could be as low as 15°C, which I understand is good: the lower the temperature, the better for the system (less risk of overheating, etc).

Fast forward to late last year. The fans were sounding clogged with dust and the temperature was gradually rising to near 40°C. Realising my system needed a good clean out, I took it back to PB Tech to get it serviced.

A friend of mine many years ago who used to build his own machines told me that when doing this, as well as the de-dusting, the "thermal paste" should also be replaced to help with keeping temperatures down (he described it as being more like grease).

The PC was returned to me after a few days, and it now has a noticeable hum that it didn't before I took it in. The temperature was (initially) slightly lower, but only down to 30°C. Today it was at nearly 39, which I've never seen before.

E-mailed PB Tech, no reply. Tried Facebook, no reply. Finally called today and talked to a guy who told me that 39°C is "a really good temperature", and he had no idea why it would have been around 50% of that when I got the machine back in 2018.

So. Am I over-reading into this? Is it something I should be concerned about, or is nearly 40°C a "normal" temperature for a desktop PC to run at?
Note that I don't play any games that might highly tax the CPU, in fact my usage is quite normal.

Any feedback appreciated, thanks 🙂