Chipsee PPC-CM5-156 Review – Part 2: A Raspberry Pi CM5 fanless Panel PC tested with Raspberry Pi OS

We’ve already had a look at the hardware of Chipsee’s 15.6-inch industrial touch panel PC in the first part of the review, before booting it to Raspberry Pi OS. I’ve now had time to test most features of the PPC-CM5-156 panel PC running Raspberry Pi OS, so I’ll report my experience testing performance and most ports of the Raspberry Pi CM5-based system in the second part of the review.

PPC-CM5-156 panel PC system info and sbc-bench.sh benchmark

Let’s check the features of the PPC-CM5-156 panel PC using the inxi utility:

Everything looks to be correctly detected, including the HDMI port connected to the built-in display, the external HDMI port, the WiFi and Bluetooth module, the CAN Bus, Ethernet, the 4G cellular modem (wwan0), the 32GB eMMC flash, and the 250GB NVMe SSD. The idle CPU temperature is reported to be 67.8°C, which feels a bit high even for a passively cooled system.

Let’s now run sbc-bench.sh to check the system and cooling performance:

The CPU temperature is really high, and CPU throttling was reported…

Something is wrong here because the large metal cover serves as a heatsink, and there shouldn’t be any throttling. The reason/excuse is my screwdriver…

When I did the teardown of the PPC-CM5-156 panel PC, I used a multi-bit screwdriver similar to the one on the left with the part holding the bit preventing it from fully reaching the screw heads as the screws are accessible through some holes in the metal cover. I could do the disassembly with some effort, and when I reassembled the bottom cover, it looked secured properly, but obviously, something was wrong. When I went to another house, I used the screwdriver on the right in the photo above to further tighten the screws. We can immediately see the difference in the chart below.

The Broadcom BCM2712 used to idle at about 80°C, and after I tightened the screws it dropped to about 40°C. We can see some oscillation on the right, and I think it’s because I turned the panel PC upside down a few times during testing, since there’s no stand.

Let’s try sbc-bench.sh again:

That’s more like it! The maximum CPU temperature was around 62.8°C during the cpuminer test at a room temperature of around 28°C.

If we look at 7-zip results, the PPC-CM5-156 panel achieved 11,310 MIPS on average, which compares to 11,160 MIPS with the Raspberry Pi CM5 IO board and an active cooler, so the system works just as expected. If you have to service it to install an M.2 module (SSD/AI accelerator) and/or a 4G LTE mini PCIe module, just make sure you have the right tools and the cover is firmly in place, or it can have serious impact on performance (the 7-zip score was 5100 MIPS the first time) and longevity of the system.

RS232 console access on Chipsee PPC-CM5-156

Going further in the review, we’ll heavily rely on Chipsee’s software documentation for Raspberry Pi OS on CM5. I did all the tests above over SSH, but if, for whatever reason, you can’t make use of WiFi and Ethernet, or type directly on the display, the machine offers an RS232 interface on the terminal block for debugging.

We’ll need to connect pin 17 (Rx), 19 (Tx), and 21 (GND) to a serial cable. Chipsee explains this clearly in the documentation. I had an old USB to RS232 adapter and a DB9<->DB9 female cable, which I wired to the PPC-CM5-156 using male jumper cables.

The screwless pluggable terminal block on the panel PC relies on a push-in mechanism. Press the orange lever with a small flat screwdriver, insert the wire, and release the orange lever to secure the cable.

But all I had was gibberish… I tried to switch Tx and Rx, but it did not help. The male jumper cables did not seem to fit well in the DB9 female pins, so I changed strategy and replaced the DB9 cable with female jumper cables, and this time around, it worked just fine.

Storage and USB testing

Let’s carry on the PPC-CM5-156 panel PC review with some storage and USB tests.

I ran iozone3 on the 32GB eMMC flash on the Raspberry Pi CM5:

337MB/s sequential read, 110MB/s sequential write, and decent random I/Os.

Let’s now switch our test to the 250GB M.2 NVMe SSD installed in the system, mostly to check the PCIe interface. It’s connected over a PCIe Gen2 x1 at 5GT/s by default:

We can run iozone3 on the NTFS partition. I skipped the read test because it’s usually garbage on NTFS since direct I/O don’t work (the data is cached):

That would be 406MB/s write, roughly as expected for a 5GT/s link.

Let’s switch to PCIe Gen3 x1 by adding the following line in /boot/firmware/config.txt in the [cm5] section:

After a reboot, we can see LinkSta is set to 8GT/s:

Running iozone3 immediately shows an improvement:

717MB/s is fine, but it’s a bit slower than when I tested other NVMe SSDs on Raspberry Pi 5 (usually around 760MB/s writes), but it might be because the drive is formatted with NTFS instead of EXT-4.

I also tried the microSD card slot. But after I inserted a microSD card, there were no messages in the kernel log, and it’s actually normal. It’s because the microSD card cannot be used for memory extension when a Raspberry Pi CM5 is connected, and only as a boot device for a Raspberry Pi CM5 Lite.

The Chipsee PPC-CM5-156 comes with two USB 3.0 (5 Gbps) ports, which I tested with a USB ORICO NVMe SSD enclosure.

Here are the results for USB A #1 (left):

and USB A #2 (right):

Both are properly detected as being 5 Gbps ports, and a 349MB/s write speed is OK (2792 Mbps + overheads), but it’s quite slower than with the Raspberry Pi 5 where I measured about 388MB/s sequential read speeds and 411MB/s write speeds. Chipsee says the two USB 3.0 ports are implemented through a USB hub, so it might explain why.

USB-C is mainly used for firmware updates. So I turned off the panel PC, pressed the PROG key, and turned the device back on to enter download mode. I had already installed rpiboot for the Raspberry Pi CM5 review, and I had no issue when running it:

We can see the eMMC flash and 250GB SSD in the host.

This would allow us to flash Raspberry Pi OS to the eMMC flash or the NVMe SSD. I haven’t done it, but you’ll find the latest system image on GitHub, or alternatively, you can install Raspberry Pi OS and install the script separately as explained in the aforelinked documentation.

Networking and wireless – Ethernet, WiFi, Bluetooth, and 4G LTE testing

The Chipsee PPC-CM5-156 panel PC supports Gigabit Ethernet, WiFi 5, Bluetooth, and 4G LTE (optional) connectivity. Let’s test them all.

I first tested Gigabit Ethernet with iperf3 directly in bidirectional (full-duplex) mode:

No problem here. Let’s now switch to WiFi 5 @ 5 GHz. We had a 351 Mbps link to mt ISP broadband router:

Let’s run iozone3 again:

• Download:

• Upload:

The results are very similar to the WiFi 5 Raspberry Pi 5 test I did before with a different router.

I could pair my Android smartphone to the CM5 panel PC over Bluetooth fine, but failed to send files. That’s because, contrary to most operating systems like Windows, Ubuntu, and Android, Raspberry Pi OS does not natively support sending files over Bluetooth. It can be done, but users need to install an OBEX server.

So instead, I just tested the PPC-CM5-156 panel PC’s Bluetooth capabilities with a Bluetooth headset. This worked fine with an ES202 headset while playing a YouTube video.

My review sample ships with a 4G LTE Cat 4 modem capable of data rates of up to 150 Mbps downlink and 50 Mbps uplink. So I inserted a SIM card from DTAC with “unlimited speed” as shown below. Note that hotplug is not supported, so you’ll need to turn off the panel PC before inserting a microSIM card.

After booting the system, we can check information using mmcli:

The important part is the Status section. If the SIM card is missing or incorrectly inserted, you’ll see:

The 3GPP section shows some information about the hardware (e.g. IMEI number) and operator (dtac TriNet).

One way to connect to 4G LTE is to use the hardwaretest application found in the Accessories menu in Raspberry Pi OS.

Click on 4G enable and Refresh buttons, and an IP address for the wwan0 should show up. From there, we can ping a server or browse the web over 4G LTE.

I ran a speed test over the cellular connection, and the results were 20.83 Mbps for download, 2.70 Mbps for upload. For reference, I repeated the test on my smartphone (OPPO A98 5G) with the SIM card, and it was quite faster at 65.96 Mbps and 7.66 Mbps, respectively.

Another method to connect to the cellular network is via the command, and it’s equally easy:

You’d need to run the command each time the system boots to have a persistent connection, and Chipsee provides instructions to do just that.

Display, Touchscreen, and HDMI

The display works fine indoors, and the touchscreen supports gestures like scrolling or zooming in Chromium or Firefox web browsers. 10-point multitouch also works using the WBBMTT website.

However, there’s a downside to having multitouch enabled in Wayland, as double-click does not work in the file manager. The latter would require mouse emulation for this to work, but it disables multitouch support. The latest version of Raspberry Pi OS is supposed to have a setting to switch between the two modes, but this was not enabled in my case.

One way to switch to mouse emulation would be to add an entry in ~/.config/labwc/rc.xml to set mouseEmulation to no for the ILITEK-TP display. Something like:

More on that shortly.

The Chipsee PPC-CM5-156 panel PC also comes with an HDMI video output, so I connected a GAOMON PD2200 pen display with 1920×1080 resolution.

The dual display setup looks to work just fine until I tried the touchscreen display. Something was off, as for instance, tapping on the “x” key on the soft keyboard would trigger the “m” key instead.

After playing a bit more with the touchscreen, I realized the resolution was set to 3840×1080 using both displays, which explains the offset I experienced above. I edited the ~/.config/labwc/rc.xml file to set the touchscreen to HDMI-A-1 only, and it fixed the issue. Here’s the content of the file:

I also enabled mouse emulation while I was at it. After a reboot, the touchscreen was now working properly, and I was able to use double-tap in the file manager. I also noticed the Mouse Emulation and Multitouch options were now available in the settings.

Chipsee PPC-CM5-156 power consumption

I measure power consumption with a wall power meter as follows:

• Power off – 4 Watts
• Idle – 20.9 – 20.7 Watts
• YouTube 1080p60 (Chromium) – 24.1 – 26.3 Watts
• Stress test (stress -c 4) – 26.0 – 26.1 Watts

The panel PC was connected to the network over WiFi during measurements, and nothing else was connected to the device.

Conclusion

Overall, I find the Chipsee PPC-CM5-156 to be a solid device, and everything I tried mostly worked out of the box with expected performance. The documentation is pretty good, although I had to fix some small undocumented issues using my experience with Raspberry Pi touchscreen displays.

I’d like to thank Chipsee for sending the PPC-CM5-156 industrial panel PC for review with a Raspberry Pi CM5 module with 4GB RAM, 32GB eMMC flash, and a wireless module. The company offers models from 5-inch to 23.6-inch with different options. The 15.6-inch model reviewed here starts at $558, and the price with the options I had (250GB SSD and 4G LTE Cat 4 module) totals $682 plus shipping.

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