Homey Pro 2023 CPU Speed Actual vs Advertised

Questions & Help
1

Since three months I have a Homey Pro Early 2023 model. I am using it in combination with the official Homey LAN/ethernet adapter and original power cord/plug.

I am struggling to understand the difference in CPU speed that my Homey runs at vs. the advertised speed on the Homey website.

Based on the website, the (max.) CPU speed should be 1.8 Ghz:

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However my Homey typically hovers beween 900 and 1500 Mhz, but never higher (I checked both Homey’s Insights, the sysInternals app and the reported speed on the Homey Developer Tools page).

As far as I can see the temperatures of my Homey are ok and all the ‘throttling’ and ‘undervoltage’ properties reported on the Homey Developer Tools page are reported as ‘false’ (which if reported as ‘true’, I understand could be an indication of an icorrect power plug):

Homey CPU Speed & Temp
Homey CPU Speed & Temp2702×1570 374 KB

Homey Trottle Info
Homey Trottle Info840×1218 54.3 KB

How should I interpret this difference? Is it normal that Homey runs at max 1500 Mhz?
I hope someone can explain it to me. Thanks.

2

Your Homey has (literally) nothing better to do :man_shrugging:t3:

Also, Insights aggressively averages older values, so if your Homey runs on 1.5Ghz most of the time it will average out around that speed, even though there might have been higher peaks.

3

Your Raspberry CM4 CPU can run up to 1.8GHz but to save power, decrease temperature, when idling, it’s lowering it’s frequency based on given CPU Scheduler (OnDemand). Rest is as Robert described.

4

That makes sense. Though the CM4 datasheet also indicates that the CPU speed is 1.5Ghz instead of 1.8Ghz:

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2 Likes
5

Interesting… :thinking:

6

Indeed. I’ll ask Athom for a clarification.

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7

I also asked on Slack :+1:t2:

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8

That datasheet is from 2023, Wiki states for RPI 4 (not CM4) that two CPU revisions exists :
Quad-core ARM Cortex-A72 @ 1.5 GHz (B0 Revision)
/ 1.8 GHz (C0 Revision)

I wonder if someone confused this info… my CM4 is running on 1.5 GHz as well

Anyone with fresh/new Homey 2023, who can confirm his CPU frequency ?

9

This is what mine says (old(er) model):

Model: Raspberry Pi Compute Module 4 Rev 1.0

Model name:                      Cortex-A72
Stepping:                        r0p3
CPU max MHz:                     1500.0000
CPU min MHz:                     600.0000

But the CM4 web page doesn’t mention that it comes in different revisions, just the 1.5Ghz one:

Broadcom BCM2711 quad-core Cortex-A72 (ARM v8) 64-bit SoC @ 1.5GHz)

With a link to the aforementioned data sheet, which I assume is current.

This is what the introduction e-mail said about the new HP (back in October 2022):

image
image1460×1446 55 KB

10

Yep, I guess so. Seems while Raspberry equip RPI4 better CPU on latest revisions, they kept CM4 running on old CPU (I physically checked one of CM4 ordered this year and it’s B3 version)

11

I replaced mine with an 8gb ram version and I have also 1.5Ghz

12

I had ordered mine this year and i have also 1.5 GHz.

13

Slack is suspiciously silent on this matter (as opposed to dashboard-related items…).

14

Same for Athom’s support desk. Still awaiting their response.

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I did note that the 1.8Ghz spec is also part of their keynote/announcement videos for the Homey Pro 2023 on YouTube and also mentioned in the specifications on the websites of Homey resellers.

1 Like
15

I asked Tweakers to update their database entry for Homey Pro, which also stated a 1.8Ghz speed. It was updated within a few hours.

16

I got word back from Athom.

In short: the 1.8 GHz spec is the maximum capability of the processor. Hence that is the number advertised.

However, they decided to cap the speed at 1.5 GHz for temperature, power consumption and longevity reasons based on their own tests and recommendations from Raspberry Pi.

Athom indicated that they are going to update their website to the 1.5 GHz spec.

1 Like
17

Sorry, but this smells like BS.

Raspberry Pi’s own documentation doesn’t state anywhere that the CM4 comes in a 1.8Ghz variant, only 1.5Ghz.

And even if Homey would have a completely custom chip (which wouldn’t make sense, because why have a custom chip that you then have to underclock to “normal CM4 speeds”?), nothing points to it being speed-limited (which, on RPi, you configure in /boot/config.txt using arm_freq, which Homey doesn’t do).

2 Likes
18

Thanks for sharing. Frankly, it’s not their decision but the Raspberry max. CPU speed set by the Vendor and I’m not really sure they can “just” update their website :wink:

Anyway, I played little bit around as I do have active cooling and…

1800GHz
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The CPU temp increased by aprox. 5C during peaks.

3 Likes
19

Yes, that does not seem logical. I raised a follow-up question to Athom. Let’s see what their response is.

20

Looking at your screenshot: you were able to let Homey’s CPU run at 1.8 GHz? I assume you made/forced some changes under the hood, as this does not seem to be an option in the normal end user UI.