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WiFi 6 is not faster than Ethernet on the Raspberry Pi

I didn't know it at the time, but my results testing the EDUP WiFi 6 card (which uses the Intel AX200 chipset) on the Raspberry Pi in December weren't accurate.

It doesn't get 1.34 gigabits of bandwidth with the Raspberry Pi Compute Module 4 like I stated in my December video, WiFi 6 on the Raspberry Pi CM4 makes it Fly!.

I'm very thorough in my benchmarking, and if there's ever a weird anomaly, I try everything I can to prove or disprove the result before sharing it with anyone.

In this case, since I was chomping at the bit to move on to testing a Rosewill 2.5 gigabit Ethernet card, I didn't spend as much time as I should have re-verifying my results.

MZHOU WiFi Bluetooth M.2 NGFF Adapter Card for PCIe Raspberry Pi Compute Module 4 AX200 Intel 6

Testing 2.5 Gbps Ethernet on the Raspberry Pi CM4

Rosewill 2.5 Gbps Ethernet adapter PCIe 1x card

I got this Rosewill RC-20001 PCIe 2.5 Gbps Network Adapter working on the Raspberry Pi Compute Module 4.

Right after I got the card working, though, I tested it in an external powered PCI Express riser, and that test released the card's magic smoke. Oops.

Here's a dramatic re-enactment that's actually pretty accurate to what it looked like in real life:

PCIe card lets out magic smoke

Luckily, buying a replacment wasn't too bad, since the card is less than $20. But to get it to work on my spiffy new ten gigabit network, I also had to buy a new SFP+ transceiver that was compatible with 1, 2.5, 5, and 10 Gbps data rates, and that cost $60!

Setting 9000 MTU (Jumbo Frames) on Raspberry Pi OS

Raspberry Pi OS isn't really built to be a server OS; the main goals are stability and support for educational content. But that doesn't mean people like me don't use and abuse it to do just about anything.

In my case, I've been doing a lot of network testing lately—first with an Intel I340-T4 PCIe interface for 4.15 Gbps of networking, and more recently (yesterday, in fact!) with a Rosewill 2.5 GbE PCIe NIC.

And since the Pi's BCM2711 SoC is somewhat limited, it can't seem to pump through many Gbps of bandwidth without hitting IRQ limits, and queueing up packets.

In the case of the 2.5G NIC, I was seeing it max out around 1.92 Gpbs, and I just wouldn't accept that (at least not for a raw benchmark). Running atop, I noticed that during testing, the IRQ interrupts would max out at 99% on one CPU core—and it seems like it may be impossible to distribute interrupts across all four cores on the BCM2711.

WiFi 6 gets 1.34 Gbps on the Raspberry Pi CM4

January 1, 2021 Update: My 1.34 Gbps benchmark was flawed. See this GitHub issue and this updated blog post to learn more: WiFi 6 is not faster than Ethernet on the Raspberry Pi.

EDUP Intel AX200 WiFi 6 802.11ax PCIe card in Raspberry Pi Compute Module 4 IO Board

After buying three wireless cards, a new WiFi router, optimizing my process for cross-compiling the Linux kernel for the Raspberry Pi, installing Intel's WiFi firmware, and patching Intel's wireless driver to make it work on the Raspberry Pi, I benchmarked the EDUP Intel AX200 WiFi 6 PCIe card and got 1.34 Gbps of bandwidth between the Raspberry Pi and a new ASUS WiFi 6 router.

This is my story.

Kubuntu Focus M2 Linux laptop review and MacBook Pro comparison

A few months ago, I replaced my Core i9 MacBook Pro with a Raspberry Pi 4 model B with 8GB of RAM for a day, and I made a video and a blog post about the experience.

Obviously there's a vast difference between a new Core i9 laptop with 32 GB of RAM, a dedicated GPU, and a 2 terabytes of fast storage and a tiny Raspberry Pi running ARM. So it wasn't a fair fight, but I could do a lot of things well enough, and every generation of Pi has gotten better.

Kubuntu Focus M2 Linux laptop

A few weeks ago, someone from Mindshare Management asked me if I'd like to do the same test, but this time with an almost one-for-one replacement laptop: the new Kubuntu Focus M2.

Review video: Check out the video that goes along with this review:

The Raspberry Pi 4 has a fan now - the Case Fan

Last year, I wrote a blog post titled The Raspberry Pi 4 needs a fan.

And in a video to go along with that post, I detailed the process of drilling out a hole in the top of the official Pi 4 case and installing a 5v fan inside.

Raspberry Pi 4 Case with Fan drilled into top of case

But that solution wasn't great. The fan was a little loud and annoying, and would stay on constantly. And who wants to damage the nice-looking Pi Case by putting a hole right in the top?