Crazy CPU temps

[Cubeputer]

Hi! I was just messing around with HWMonitor, and I found that when I'm idle, my temps are jumping around. It will start at around 70c, then drop down by 10c per second. Then it will jump up about 10c, sometimes even more, and on one of the jumps it reached 87c. Does my cooling fan suck, or is there a faulty temp sensor. All these temps were recorded on idle with only HWMonitor and 1 tab in chrome at around 10% CPU power.

 

[neeyik]

First thing to do is to use another program to verify the readings. You could try AMD's own tool:

https://www.amd.com/en/technologies/ryzen-master

But let's assume the readings are correct. What cooler are you using? If it's the Wraith Stealth, then it should be more than enough for that CPU:

Ryzen CPU + Vega Graphics on a Chip: AMD Ryzen 5 2400G & Ryzen 3 2200G Review

Benchmarks: Power Consumption & Temperatures. Updating its entry-level and mid-range product lines, AMD's new Ryzen 5 2400G and Ryzen 3 2200G APUs are set to replace nearly all of the company's offerings...

www.techspot.com

It's possible that there is glitch with the temperature readings, but unlikely, so it's worth having a look at the fan speeds in HWMonitor - is it correctly spinning up/down? Check the fan profile in the motherboard BIOS - is it set to increase with temperature or stay at a low or constant rpm?

If all of these issues are fine, then it's time to take the heatsink off and have a look at how the sink and CPU connect. If it's a poor contact or the thermal paste has dried out, then that will be the problem. The paste is easy to rectify, clean it off and get some new stuff on. If it's a poor contact, then you'll need to have a good look at how the heatsink is mounted on the motherboard.

 

[Cubeputer]

The fan speeds are staying very low. I will use amd's tool.

 

[Cubeputer]

The fan speeds are not changing when it get way too hot.

 

[Cubeputer]

Wait a second. After watching it for a while it is still fluctuating the same way it was. Just at lower temps

 

[neeyik]

The fluctuations are perfectly normal - modern CPUs vary their clock speeds and voltages constantly, to ensure maximum performance depending on the workload. So something as simple as opening a new window can induce a spike in temperature.

But as they're designed to do this, it's not actually a problem, and it's easy to fall into the mistake of comparing this behaviour with previous processors, which had far less variation in their clock rates.

As long as the temperatures themselves are acceptable, I wouldn't worry.

 

[Cubeputer]

Okay, thanks. So the varying clock speeds and varying temps are all ok, unless they get too hot, right?

 

[neeyik]

Correct - as long as the CPU doesn't hit its temperature limit (at which point, it will decrease clock speeds and voltages to prevent damage), everything is fine.

That said, high idle temperatures aren't a good sign, and if you were getting between 60 and 80 degrees Celsius, then I would take a good look at the fan profile in the motherboard BIOS and the contact between the heatsink and the CPU. A sensible range of idle temperatures for most CPUs is between 30 and 40 C.

 

[Cubeputer]

That's what I thought. The temps seemed too high. I think the fan doesn't spin Fast enough. I am seeing idle temps between 60 and 75 Celsius. That seemed a bit too hot to me.

 

[Cubeputer]

Do you have any explanation about the weird temp jumping and the different temps from the Mobo and Package sensors? The package sensor seems to get into these weird cycles. At the start, the temps are pretty high for idle, but not moving at all. Then it gets into these repetitive sequences. But the sensor for the CPU on the Mobo reads a steady, significantly lower temp.

 

[neeyik]

The difference in reported CPU temperatures mostly comes down to the sampling time - the CPU package one is being reported directly by the CPU, and it probably updates the value every few milliseconds. This is to ensure the CPU can shut itself down quickly enough, if it overheats.

The motherboard's thermal sensor for the CPU will be sampled at a much slower rate, as all it's doing to checking the overall temperature of the chip that's plugged into it.

All modern CPU+motherboard combinations do this: for example, the system I'm currently gives these readings:



Note the difference in max temperatures between what the motherboard is reporting, compared to what the CPU is reporting. The faster sampling rate of the CPU has picked up the temp spike, whereas the slower motherboard hasn't.

 

[Cubeputer]

Ok, thanks. That makes sense.

 

[Cubeputer]

Right when I got on, the temp was 84c, but the fan was only spinning at 430 rpm. The CPU is too hot because the fan is spinning too slow. Is there a way to manually turn up fans? Or should I even do that?

 

[neeyik]

Yes, you definitely should - 430 rpm is right down at its slowest rate. It easily goes up to 2000 rpm:

AMD Coolers Tested: Wraith Prism vs. Wraith Spire vs. Wraith Stealth

AMD upped the game with the stock CPU coolers it bundled with Ryzen processors and they kicked it up another notch with 2nd-gen Ryzen which come with...

www.techspot.com

You can change the fan's setting either in the motherboard BIOS or by using a program called SpeedFan:

SpeedFan

Free program that monitors voltages, fan speeds and temperatures in computers with hardware monitor chips.

www.techspot.com

SpeedFan doesn't work with every system, so if it doesn't let you set the fan's RPM (and you can set it do this on the basis of the CPU temperature), then you'll have to set in the BIOS.

 

[Cubeputer]

Ok so I got the fan speed up to 1700 RPM and it helped, but the temps are still in the 45-60 c range.

 

[neeyik]

Is that at idle?

 

[Cubeputer]

Yes, That is at idle

 

[neeyik]

That's definitely too high - it's not damaging to the CPU itself, but it leaves little headroom for the inevitable rise in temperature when it's under a heavy load. Do you have Ryzen Master installed? If so, what are the reported clock speeds, TDC, and core voltage when at idle?

 

[Cubeputer]

I have ryzen master.

 

[Cubeputer]

Clock speed: 2.98 ghz TDC: 10% Core voltage: 1.45v

 

[Cubeputer]

I'm pretty sure those are the specs but I attached the screenshot

 

[neeyik]

They’re all normal values, but by default the 2400G runs at a pretty high core voltage of 1.45 volts; you can lower this in the motherboard BIOS to reduce the heat issue.

If you’re not aiming to run the CPU permanently overclocked, you could start at 1.35V and see how stable the system is. If it’s unstable, raise the voltage by +0.01 and check again; repeat until you’re happy.

 

[Cubeputer]

Ok. I'm not planning to run overclocked. So you're saying my temps are because of voltage?

 

[Cubeputer]

And also the counting down and then fast jumps are okay?

 

[neeyik]

The rapid changes might be fine, as this is something that modern CPUs do, but I wouldn't discount that there is something going on in the background that could be exacerbating it.

The default voltage is 1.45V and, in theory, that shouldn't be causing the idle temperatures you are seeing. However, you can set it lower, and this will definitely drop the temps - well, it should do!. If it doesn't make any difference, then something is definitely amiss with the cooling system.