I currently do not have a fan on my VisionFive 2. Should I be worried about overheating it, if I start using the CPU at 100%?
Will it thermally throttle, to stay safe?
If so, how can I see if it’s thermally throttling?
From the Vision5 datasheet.
5.14. Temperature Range and Thermals
The recommended ambient operating temperature range is 0 to 50 degrees Celcius.
To reduce thermal output when idling or under light load, VisionFive 2 reduces the CPU clock speed and voltage. During heavier load, the speed and voltage (and hence thermal output) are increased. The internal governor will throttle back both the CPU speed and voltage to make sure the CPU temperature never exceeds 85 degrees C.
VisionFive 2 will operate perfectly well without any extra cooling and is designed for sprint performance - expecting a light use case on average and ramping up the CPU speed when needed (for example, when loading a webpage). If a user wishes to load the system continually or operate it at a high temperature at full performance, further cooling may be needed.
So you should be safe.
3 Likes
Thanks.
Only remaining question then is being able to detect when it’s happening.
1 Like
That I can’t help with…
I guess it can be detected via acpi or with a specific command (like vcgencmd on the PI), but we may need to wait for support to arrive in the firmware/etc…
Maybe you can create a temperaure checkup script. It’s readable with:
cat /sys/class/hwmon/hwmon0/temp1_input
2 Likes
Great find, thanks.
Under full CPU load I’m seeing this:
$ cat temp1_input;sensors
69846
120e0000.tmon-isa-0000
Adapter: ISA adapter
temp1: +69.8°C
1 Like
Without heatsink? CPU-only load?
Yup. POVRay maxing out all “harts”. No case, sitting on a desk. I’ll render a frame or two of quake demos, to compare speeds. qpov.retrofitta.se has some stats.
2 Likes
Seems fairly good w/o even a heatsink.
As this SoC targets a 85C maximum according to other posts, I suspect a simple heatsink would be sufficient for peace of mind, not needing a fan.
I put this small (but not too small) with a little fan, because I rebuild my kernel almost every day with make -j4.
without AC, make -j4 causes CPU to 60C, with AC on and the room temp was around 24C, the CPU temp never higher than 55C.
7 Likes
I meant to say qpov.retrofitta.se will have some stats. It has other stats now, but since no render has finished on the VisionFive2 yet there’s no stats for it. Will take a few more days.
is that secured and is there a “standard” for the CPU cooling these types of devices require, or are compatible with? [please ignore the highlight]
You can use a “normal” Nothbridge Heatsink. More Infos at the " Using Odroid XU4 fan on VisionFive 2" Thread
You were also surprised, that the negative an positive wire on jst connector is reversed? 
no, it isn’t. Pin 1 on GPIO is +3.3 and pin 6 is ground. I use +3.3 because with +5 my fan was too noisy.
1 Like
Hi @cwt may I ask you what model fan are you using here? Could you share the link in where you buy it please
It just a very cheap one from an online store in my country. It’s important to choose a suitable heatsink to dissipate heat efficiently from the CPU. The height of the fins should allow for maximum air contact, and it’s recommended to avoid low profile heatsinks. Additionally, the use of double-sided thermal tape can help ensure a good thermal connection between the CPU and the heatsink.
Maybe a additional small optimization is to use a 2 mm thermal pad (not a thermal tape). it’s a bit fluffy and covers more of the different heights in the heatsink region.
I get very good temps with a heatsink like cwt’s, a noctua fan and the thermal pad:
riscv ~ # uptime
20:23:31 up 4 days, 2:35, 1 user, load average: 3,91, 2,93, 1,53
riscv ~ # cat /sys/class/hwmon/hwmon0/temp1_input
26337
For what it’s worth, I got this: https://www.amazon.com/gp/aw/d/B07XY9FHPZ and it never got above 58°C now under load. That’s plenty cold.
ADD: sorry! It’s a link to a pure(? really?) copper heatsink (no fan) for about $10 (for two). Comes with two adhesive thermal pads (seems to work ok).
I did measure before and after and the impact was about -10C.
5 Likes
I have a 2 mm thermal pad, but I don’t know how to make it stick securely with my heatsink and CPU. My heatsink doesn’t have anything to screw to the board, so I use double-sided thermal tape because it is already have glue on both sides.
1 Like