Few weeks ago, I got gigabit internet. After technician finished settings it up, I did plug-in my computer to new modem/router and able to see close to gigabit speed (around 920-940 megabits). Awesome. Then I did make sure that I made modem/router as dumb as can and connected my PC to my router. After that I did run speed test again. To my surprise I got about 260-280 megabits per second. What the hell? And I started investigation.

My current version was OpenWrt 18.06.4 and I started to check everything. To make long story short, at the end, I found out that CPU load is 100% during speed test. I used command top from SSH to confirm that