A part order arrived today that provided some additional resources to proceed with the testing.


I ordered PoE power supply on April 3 and the Pi4B power supply on April 15, from Newark Canada, guess which one arrived first? The Pi4B power supplies!


Both items where listed as in stock. The PoE power supply is listed as "In Processing" for order status. The man responsible for managing RoadTests Mr.rscasny  has offered to look into the anomaly. Nothing like a man in high place to get things done. It is good that he is in a high place because he is rather short.


While I wait for the PoE power supply order, I figured I could do the same bench load test on the Pi4B as I did in the posting of The Road to Raspberry Pi4B/ PoE Hat RoadTest Review (comparison Pi3B+) . I think I will also repeat what I did in The Road to Raspberry Pi4B/ PoE Hat RoadTest Review (Squirrel Moment) to remain consistent.


I'm going to shorten the dialog in this post and just provide results. I'm hoping this will drive viewer traffic to my other posts thereby increasing my numbers look. I haven't figured out how that will help but I'm thinking more is better.


An interesting observation. An nmap scan was performed to find the Pi4B in the network after boot up.

The operating system on IP is (Unknown). This is the Raspberry Pi4B. The device on is a Raspberry Pi3B+. I'm always sceptical when the statement ", oh there the same" is used to describe upgrades. Here nmap is not identifying the Pi4B network interface. The Ubuntu system software is up to date. Maybe a source version of nmap detects the new Pi.


Here are the result of the stress test application on the Pi4B with no ancillary heatsinks. The Pi3B+ had heatsinks during its tests. The temperature on the Pi4B remained below 80 Degrees Celsius, with no throttling. Let us see what cpuburn produces.

The cpuburn test was ran for 17minutes with the results shown. The temperature reached 80 Degrees Celsius with no throttling. This is impressive considering the Pi4B has no ancillary heat sinks.


In the interest of post brevity, I skipped the stress test on the Pi4B & PoEHat combination. I figured since a stand alone Pi4B without heat sinks didn't throttle at 80 Degrees Celsius what benefit is there to repeating the stress test. I did want to see on board power supply voltage readings when the cpuburn application is loading the CPU's.


As demonstrated in the terminal output the Pi4B temperature remained well below throttling with the PoE Hat fan blowing air. The power supply reading was a disappointment or should I suggest a bonus. The power supply voltage dropped from 5.23 to 5.17VDC when the cpuburn application was applied.


You would expect a better showing of supply voltage regulation on the Pi4B. It causes me to question if the cpuburn application is the load test for this project. My goal is not to find the best load tester for the Pi but rather a tool to generate a load. I'm hoping with the addition of LED on GPIO pins there is sufficient load to tax the PoE Hat power supply. Recall this is a RoadTest review of the PoEHat and not Pi's.