Question When Will BIOS Kick-in Heat Kill Switch?

accesscpu_

Honorable
May 7, 2019
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I have a AMD Ryzen 9 5900X in my system, with plenty of air-flow and four case fans. This thing runs out, which I've accepted. When rendering videos, I've hit as high as 90C. But according to this article on PC Gamer, AMD is fine with that and considers "typical and by design" according to them (their words not mine).

My question is this...

I checked my bios and the thermal throttle is set to auto, but I always assume that at 90C, the desktop would kick off. That's what used to happen on my old computers back in the day.

Is 90C no longer the danger threshold for cut the system off, and is it just throttling down now as the new heat-management method? And at what point will it just shut down, if not at 90C?
 

Ralston18

Titan
Moderator
Update your post to include full system hardware specs and OS information,

PSU: make, model, wattage, age, condition (original to build, new, refurbished, used)?

Disk drive(s): make, model, capacity, how full?

Update your post to include full system hardware specs and OS information.
 
I have a AMD Ryzen 9 5900X in my system, with plenty of air-flow and four case fans. This thing runs out, which I've accepted. When rendering videos, I've hit as high as 90C. But according to this article on PC Gamer, AMD is fine with that and considers "typical and by design" according to them (their words not mine).

My question is this...

I checked my bios and the thermal throttle is set to auto, but I always assume that at 90C, the desktop would kick off. That's what used to happen on my old computers back in the day.

Is 90C no longer the danger threshold for cut the system off, and is it just throttling down now as the new heat-management method? And at what point will it just shut down, if not at 90C?
Tjmax is 90c but that's only heat throttling threshold. it would shut down at about 110c.
Which kind of cooling do you have, a half decent CPU cooler should be able to keep up to 80c, In mean time you could use Curve Optimizer to keep voltages lover, typically -10 to -30. all core.
 

accesscpu_

Honorable
May 7, 2019
203
6
10,585
All four air cool fans (be Quite brand). I only hit 90C for a few seconds, and average mid-80s at max load. So until the time comes I wanna go with a water cooler, I guess this is as good as she gets. Thanks for the info all!
 
All four air cool fans (be Quite brand). I only hit 90C for a few seconds, and average mid-80s at max load. So until the time comes I wanna go with a water cooler, I guess this is as good as she gets. Thanks for the info all!
What is your CPU cooler ? I suppose it's an 3rd party air cooler, much depends on it, case fans just help a bit, with an open case side they do almost nothing. That is best way to check how much case airflow is efficient.
Are those "all four" case fans ? If connected to a header that is not CPU_FAN , they should react on MB temperatures (VRM and/or Chipset temperature sensors) .
 
On short, it will not shut down so easily, there is a thing called thermal throttling which reduces cpu frequency to lower temperature to stay under 90 degrees, if cpu reaches minimum frequency and still goes over the temperature set in bios ( 90 degress by default) then it will shut down how it was said at 110 degrees.
 
I have a AMD Ryzen 9 5900X in my system, with plenty of air-flow and four case fans. This thing runs out, which I've accepted. When rendering videos, I've hit as high as 90C. But according to this article on PC Gamer, AMD is fine with that and considers "typical and by design" according to them (their words not mine).

My question is this...

I checked my bios and the thermal throttle is set to auto, but I always assume that at 90C, the desktop would kick off. That's what used to happen on my old computers back in the day.

Is 90C no longer the danger threshold for cut the system off, and is it just throttling down now as the new heat-management method? And at what point will it just shut down, if not at 90C?
There are several temperatures at which different things happen. Tjmax is indeed 90c, that's when the processor starts throttling itself pretty heavily and won't even reach it's rated base clock speed of 3.7Ghz to keep it below that. Tjmax is an operational limit, not really a safety limit per se.

And then even at temperatures well below Tjmax it's already pulling back on boosts to it's rated single-core max boost clocks (4.8Ghz). By somewhere in the low-mid 80's it's probably rarely hitting those clocks, or pulls the boost back much sooner when the core temp gets that hot in the middle of it. That's why better cooling is so important for it. It's the same as overclocking since it just boosts higher/longer for you even though you may not see much if any change in temperatures while monitoring.

But above the 90c Tjmax are two other true safety limits: one is the CPU Thermal Trip, at 105c, and the other is the CPU HTC (High Temp Cutout) thermal limit at 105.5c. With proper operation of cooling solution you've put in place you should never see that because of how Tjmax operational limit and boost algorithm works. I've certainly never seen these in my system but if the processor sees one of those temps even for a brief instant it should shut off the processor (lock it up).

It might restart the system at HTC. But the thing is, the processor is incredibly dynamic and might see temps above Tjmax but below trip and HTC in brief excursions so lock-ups and especially shutting the system off has to be done judiciously so it doesn't turn off cooling pumps and fans. I'd expect the BIOS to take care of that: so when notified of a trip by the CPU the BIOS shuts everything down but runs fans/pumps to the max or something like that. If true, it's one reason it's good practice to use the motherboard fan headers to control at least the CPU fan and pumps.
 
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