This means it can run 64-bit Pi OS, but it is memory-limited and even some of the benchmarks I ran needed extra swap space to complete. But for anything that does run in the 512 MB of LPDDR2 RAM, it is at least twice as fast as the Zero/Zero W, and sometimes 3-8x faster, depending on how things handle threading (4 cores is better than 1!).
My biggest concern is overheating—even at the base 1 GHz clock, it will start to throttle after a few minutes in a case with no airflow or heat sink. You can overclock to 1.2, 1.4, or even in some cases 1.5 GHz, but it starts throttling a lot more quickly unless you have really good cooling.
The Pi Zero 2 W doesn't seem to do anything at all (no LED activity, no HDMI output) unless there's a microSD card inserted with a valid bootloader and DTB that supports it.
I just finished watching your YouTube video, so thanks for providing all of this insight. A new Pi Zero will certainly make small handheld emulators a lot more promising...
I've done some fairly fancy Python app development under Linux on a 300mhz embedded ARMv6 board with 64MB of ram, so for lots of things the Pi Zero is already overkill. But an actual OS (i.e. Linux) does make programming a lot easier than an MCU board with an RTOS. So how about a "Pi -1" (minus one) with 1/4 of the resources and power consumption of the Pi 0?
Also, I'm curious what use-case do you have that would need an RTOS?
If you need more memory just get the pi4 and a suitable power brick for it
Zero W goes up to 160 mA at load, while Zero W 2 gets up to 400-500 mA due to the three extra CPU cores.
Edit: That works! See: https://www.jeffgeerling.com/blog/2021/disabling-cores-reduc...
Another comment says /sys/devices/system/cpu/cpu[0-n]/online doesn't work, but I think you can get pretty far by changing the CPU affinity at the cgroup or process levels (for userspace) and on /proc/irq/default_smp_affinity (for interrupts). There are likely some kernel threads that would still run on the other cores, but this is reasonably close.
In particular, looks like setting CPUAffinity= /etc/systemd/system.conf will set a default for all of userspace that you can override for particular things as desired.
zstd could be slightly slower, although according to some benchmarks, it decompresses faster.
zram is the compress-in-memory like you have in Windows and ChromeOS and zswap is the compress-on-disk in case you want to replace SD cards.
zswap is a compressed (memory) cache that uses the frontswap API to evict least recently used pages to a swap device. Evicted pages are not compressed.
zram is more of a general purpose component; whereas zswap is a more specialized component.
I have been using 3As because of the reduced size (and the full sized HDMI port, which comes in handy), so I hope those get updated to a 4-grade chipset —- I feel that there is a gap between the Compute Module and the A that needs filling.
It seems like there's still one product, but increasing divergent use cases for that product.
There have been a lot of commenters in this post basically complaining that there are too many Raspberry Pis. From a practical standpoint, I don't get the complaint (I mean, how does that personally harm them in any way?).
The Raspberry Pi foundation's mission is to increase technical literacy worldwide by making and selling very low-cost yet reasonably high-performance computers. They also do quite a lot of education and outreach themselves.
What people here seem to be forgetting is that these things take money and instead of spending time fundraising (a huge cost and time sink for most non-profits), they decided to tap into the maker and computer geek communities, as well as industry. When people like you and me buy these boards to play with or build into our projects, we are subsidizing all of the foundations design, education, outreach, activities. Also when companies build products and internal solutions around the Pis. The whole reason they still sell the (mostly) original Raspberry Pi board is because there are systems, processes, or fleets still using them. They'll continue to use them until a design change is required. As long as its relatively easy for the foundation to squeeze out a new batch every so often (all of the hard work of designing them is already done), what does it hurt?
Inside a case, it quickly heats up under load!
In all cases, the CPU frequency starts stepping down when the temp hits 80C, and on the default clock it will go to 800 MHz until the temp is 79C. If it reaches 85C, it will throttle severely, all the way down to 400 or 600 MHz, I believe, until the temps get back down to 84C.
It's felt really weird seeing so little progress in available low power ARM over the years. Atmel/Microships SAMA5D3 / SAMA5D2 with it's 600 MHz Cortex A5 (2009) still seems like- half a decade latter- one of a rare few genuinely low power Linux running SoC available for purchase/use. I'm forgetting what's available in the Cortex A7 line, which is a little higher power but which still has some very low power chips available for it, & at significantly higher performance ranges. A7 has a lot of chips you can't buy, only available in some tablets & or hard to get wearable chips, but I think there are some good offerings about too. ST has the ~$20 STM32MP1, to name one.
Yet I just see so much non-materialization, non-availability. It feels like the rule. 2015's Cortex A35, 2016's Cortex A32, 2019's Cortex-A34... none of these chips seem to have really materialized in any genuinely available form. There are some off-brand tablets with A35 chips but generally that's about it. The low power segment has been rather ignored.
If you're looking for low power ARMs, maybe other boards may fit the bill better.
Both idle a little higher if you're actively using HDMI and WiFi.
As for the relative unpopularity of Cortex A3x series, I suspect that might partly because Cortex M series has been creeping into similar performance territory, like for example the i.mx rt mcu on Teensy 4.x, which has Cortex M7 running at 600 MHz.
The RPi zero shines for Python scripts that access hardware - for sensors and camera projects that are low power and cheap to make. It was actually perfect for the GrowLab project that we did over the summer with 20 others from the community https://growlab.dev - sensor data and camera images were aggregated to a more powerful RPi3/4 and then either uploaded to a static GitHub Pages site, fed into InfluxDB to create beautiful charts with Grafana.
The new Zero 2 means that I can start to run ARMv7 or even ARM64 containers on the zero again, but with the limit of 512GB of RAM. The launch blog post explains why this couldn't be made higher.
The first thing I tried out was not K3s, which I knew already suffers on a Raspberry Pi 3, but faasd. Faasd is OpenFaaS but built for pure containerd, no multi-node networking and no Kubernetes. It works fairly well for a few functions, even with NATS and Prometheus being deployed as part of the stack.
So whilst you're not going to be building K3s clusters with these, they can run containers - with Docker, containerd, nerdctl and even as a full application stack with faasd.
Where this gets more interesting for me, is hosting small applications, integrations or APIs. Perhaps with Ingress via a tunnel that can penetrate NAT/firewalls like Inlets, Argo or Ngrok.
I've ordered one of the release models to see how it performs. Look out for a blog post from me soon.
My //e had (technically still has) 320K. Most of the time, it was a ramdisk.
Of course I haven't tried banking in anything over 48KB yet so I don't even know if my circuit works, but it boots!
Spec of the Radxa Zero ($15):
CPU: Quad Cortex-A53 1.8 GHz, 12nm process
GPU: Mali G31 MP2
RAM: LPDDR4 512MB/1GB/2GB/4GB
Storage: eMMC 5.1 8/16/32/64/128GB and uSD card
HDMI: Micro HDMI, HDMI 2.1, 4K@60 HDR
Multimedia: H265/VP9 decode 4Kx2K@60
Wireless: WiFi4/BT4 or WiFi5/BT5
USB: One USB 2.0 Type C OTG, one USB 3.0 Type C host
GPIO: 40Pin GPIO, ADC/UART/SPI/PWM
Others: Crypto Engine, support external antenna, one button
CPU: Broadcom BCM2710A1, quad-core 64-bit SoC (Arm Cortex-A53 @ 1GHz)
RAM: 512MB LPDDR2 SDRAM
Storage: None, MicroSD card slot
HDMI: Mini HDMI port
Multimedia: H.264, MPEG-4 decode (1080p30); H.264 encode (1080p30)
Wireless: 2.4GHz IEEE 802.11b/g/n wireless LAN, Bluetooth 4.2, BLE
USB: 1 × USB 2.0 interface with OTG
GPIO: HAT-compatible 40 pin I/O header footprint
Other: OpenGL ES 1.1, 2.0 graphics, CSI-2 camera connector,
composite video and reset pin solder points
The Radxa is a better value if pure performance is the only criteria.
But the real value of the Raspberry Pi products is the ecosystem and code support. It will be much easier to find tutorials and software support for the Pi Zero 2 W than the Radxa and the Pi will be supported for a long time after the Radxa has been discontinued.
Also in availability. I just clicked buy and will have a Raspberry Pi Zero 2 W shipping to me in two days. I looked on seeedstudio for Radxa products; literally nothing is in stock.
As for long-range antennas, you can check out Yagi's or Cantenna, also very nice DIY projects. The longest range can be achieved by dishes. Though check your countries dBi limit that is allowed to be emitted in any direction and then reduce your tx power to stay below that. The directivity will still help reducing interference from other directions. I like the APA-M05 for its compactness.
For the cooling, I use DHT22s and simply run a bunch of fans via a PWM-driven MOSFET, directly from the Pi, roughly following the video: https://www.youtube.com/watch?v=oJ32CMxliCQ
I send notifications (actually, not SMS) via qpush.me.
I understand it's a global chip shortage, but when zero W came out, there wasn't one.
In general the RPI Zero series is really great value for a tiny linux machine.
I do want this, I think it's taken for granted how easy this thing can connect to a camera. I bought a Teensy/blue/BeagleBone/etc.. thinking "Oh I'll just plug in a camera into it". For the Teensy it won't but maybe the Beagle bone. I was using a single core Pi Zero so it was noticeable doing things like iterating over frames. Granted it can just be poor code on my part/noob in OpenCV.
buy directly from Makerbright: https://makerbright.com/raspberry-pi-zero-2-w-.html
or place an order, which will ship in early November, from:
* Sparkfun https://www.sparkfun.com/products/18713
* PiShop https://www.pishop.us/product/raspberry-pi-zero-w-2/
* CanaKit https://www.canakit.com/raspberry-pi-zero-2-w.html
Part of me feels bad whenever I use these so much computing wasted, like I have one taking a picture of an indoor garden/turning a light on/off with a cron job/Apache server and that's it. Oh well, good time for tech anyway.
If you stacked multiple Pi boards on top of each other, connected through the GPIO HAT connector, could you network them?
Apologies, just woke up and coffee not kicked in. This is probably silly :)
EDIT: yes, I should search for this sort of thing before posting: https://forums.raspberrypi.com/viewtopic.php?t=127660
tl;dr "serial port, RS485 + SLIP of some sort, probably would max out at around 1Mbps, 4Mbps theoretically possible with small MTU's" and "There is no hardware reason why an RS485 network could not be used as the physical layer for at least 32 nodes, and with some of the RS485 driver chips, 127 nodes (they have stronger drivers)"
The issue with "stacking" is the pins on each board are not part of a bus but individual programmable io pins. Any stacking would require an intermediary board to isolate all these pins safely while adding the necessary TTL serial to 485 interface chips (e.g. Maxim max485).
CAN is similar to 485 where it's a 2 wire bus though it has smarter hardware which enables full duplex communication and any device can listen or transmit. Unfortunately it is pretty slow compared to Ethernet but plenty fast for its intended use.
This would also require one of those tty-to-usb cables?
I presume they didn't make the pre-soldered header available at launch due to high demand and the ongoing chip shortage. Much easier to produce one less complex package.
Despite having just 512MB RAM, I think it's perfect for the its common use cases. For me, the CPU increase will be helpful for getting it set up and installing software (especially if it needs to be compiled), not so much for when it's actually being used.
Here in Australia, seems like it is available from Nov 8 at Core electronics 
One thing that's been interesting is that despite the 2x markup of anything pi related where I live, the pi pico was available almost immediately at about $6. I guess I'll be going a bit lower level then.
That's pretty sad.