T520-LL-CR overheating solved for less than $20

[torchsong]

Found a good deal on the T520-LL-CR, so I decided to try it on my PC.
I like to build silent computers, sensitive to noise. To achieve the cooling I want, I also use high quality fans, so that even the hottest GPU never had an issue with my PC. Thinking that it’s good enough for T520-LL-CR, I installed it and then tested for multiple hours.

Hours turned into days of testing. No idea why my PC had mostly-fast-sometimes-slow network speed, even intermittent dropouts. I tried turning up the case fan speed, changing the placement, updating OPNSense and various software, nothing.

One day for an unrelated reason, I was going through the Windows Event Viewer, found out that my NIC was sending out logs (chvbd) that the temperature was too hot. My case went through one of the hottest CPUs and GPUs and never had any throttling issues due to the heat, so it was definitely a surprise for me.

So I bought a 40x10mm fan with a few zip ties, thinking of starting from small then size up if it doesn’t work. Turns out, 40x10mm was good enough! My neighborhood had a record-high temperature yesterday, T520-LL-CR still running, hitting maximum throughput, A+ bufferbloat.

Search results recommended getting a server-grade case or/and fans, but in my case a $14 fan + zip ties fixed the issue. If you have unexplained dropouts, network issues and have no logs to go through, I say give it a try. Night and day difference!