I stopped using Speedfan years ago because I don't think it's very good. The Core 0 and 1 temps I think are probably accurate as well as the HD0 temp (hard drive temp sensor). The CPU sensor could be a diode under the chip on the motherboard (or somewhere else entirely). The one labeled Chipset might be that diode as it's almost the same as the cores themselves but it is more likely a diode for the motherboard's chipset, which isn't uncommon for them to get pretty hot. The heatsinks that come on the chipset are sufficient. You can try checking with other programs like Hardware Monitor, CoreTemp, Speccy, etc. Some programs are better than others when it comes to hardware compatibility and temperature sensors. I personally use AIDA64, which I really like, but it isn't exactly cheap.
My main concern is that, is it fine for Aux and HDD to reach 50C? And does ethernet stop working if it overheats? I'm having this ethernet disconnection problem. Thank you for helping
50c on a Mobo is fine. IF you can enter your bios and if it has readings for your hardware, that is where you aught be looking at temperatures. Make sure your bios is up to date, nic drivers are up to date and so on. Reboot your router/modem.
Those temps are fine. The ethernet disconnecting is something else like a bad driver/cable, virus, antivirus/firewall, or problem with router/modem. I'd put my money on the cable or router (but that's just a guess).