Question Limit Ryzen 5900x but Allow PBO

ojr10000o

Commendable
Aug 25, 2018
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1,510
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Is there a way to limit max frequency/max voltage while still allowing PBO to run in ryzen 5900x?

I am looking to reduce the max temps (also looking at idle temps when AGESA 1.1.8.0, PBO2 and Offset Voltage come to my motherboard later) which sometimes spike to 85C+ under load. I know it is not a problem, but I would prefer to keep it under 80C. Is there a way to thermal throttle at 80C, cap the max frequency or the max voltage while still allowing PBO to run in ryzen 5900x? I have tried to reduce Max CPU State in Windows Power Plan to 99%, and it plain out disables boosts and stays at base frequency.

CPU: Ryzen 5900x
Motherboard: Aorus X570 Pro Wifi
Cooler: ARCTIC Liquid Freezer II 240mm stock fans

Edit: Added Cooler
 
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EridanusSV

Upstanding
Aug 16, 2020
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What do you mean cap? What's your manual clock rn?
+
What's your cpu cooler?

Most software on pushes 5900X up to 4.3/4.4GHz on Auto, anything higher than that all-core is definitely going to be hot.

And I don't know why people keep capping voltage too, that thing can run on 1.5V 24/7 for the next few years as long as you have great cooling.

If Ryzen Master reports that it goes less than 1.00V on idle then everything is fine and the system is not overvolting it when running benchmark apps. If RM or Hw64 reports 1.45V then it actually needs 1.45V to run all core when running a benchmark app. On gaming, it will fluctuate from 1.1 to 1.4V which is normal. This is a 12 core beast chip. It needs the juice.

I suggest:

Voltage = Auto
PBO's PTT, TDP, EDC = 395, 255, 230
Scalar = 2x
Everything else on auto or enabled (I'm not familiar with GIGABYTE's BIOS)
 
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There is a Max Platform Thermal Limit setting. In my BIOS it's hidden until I enable PBO in Manual mode. Set that to 80C and you're done.

Ryzen monitors itself and limits voltage to maximum safe FIT values based on temperature but only so long as you leave the VCore voltage slider on AUTO. If you set it to a fixed value you're taking chances. You can use an offset to change it but positive offsets basically lie about the voltage it delivers when the processor asks for a certain voltage to be safe. That's dangerous too, so do it with as much caution as you would a fixed voltage.

BTW: I've read in several Reddit threads where AMD has stated that it's not unexpected to see temps upwards of 105C on 5900X's. It's kind of surprising to me and I've been looking for the actual thread where u/AMD_Robert (Robert Halleck, AMD tech. marketing engineer) says that and haven't found it yet. If anyone has a link, would sure be nice if you'd share it!

EDIT: I just duck-ducked it and found this: https://www.pcgamer.com/amd-views-ryzen-5000-cpu-temperatures-up-to-95c-as-typical-and-by-design/

I'm gonna go with 90C (for 5900's) now until I find that 105C reference. I think maybe some people might be confusing ryzen 5000 and RX-5700's. At any rate, I'd be more inclined to set a platform thermal limit of 90C than 80C if this is what Halleck is saying.
 
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EridanusSV

Upstanding
Aug 16, 2020
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And to be honest, if you have a great cooling. That card can run on Auto just fine and you'd still be at the top of benchmarking leaderboards. That chip is designed, manufactured, and delivered to you with the highest performance off the bat.

It's pointless overclocking those chips or setting them to manual. I know, because I own a 3950X. Only difference is the shared memory bandwidth and more optimization. Just download Ryzen Master and select AutoOC policy, it'll also unlock the PBO to run on its fullest capacity. You should be only hitting 70 to 75c all core on max.
 
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ojr10000o

Commendable
Aug 25, 2018
10
0
1,510
0
What do you mean cap? What's your manual clock rn?
+
What's your cpu cooler?

Most software on pushes 5900X up to 4.3/4.4GHz on Auto, anything higher than that all-core is definitely going to be hot.

And I don't know why people keep capping voltage too, that thing can run on 1.5V 24/7 for the next few years as long as you have great cooling.

If Ryzen Master reports that it goes less than 1.00V on idle then everything is fine and the system is not overvolting it when running benchmark apps. If RM or Hw64 reports 1.45V then it actually needs 1.45V to run all core when running a benchmark app. On gaming, it will fluctuate from 1.1 to 1.4V which is normal. This is a 12 core beast chip. It needs the juice.

I suggest:

Voltage = Auto
PBO's PTT, TDP, EDC = 395, 255, 230
Scalar = 2x
Everything else on auto or enabled (I'm not familiar with GIGABYTE's BIOS)
I meant limt. I am using an ARCTIC Liquid Freezer II 240mm. I know those are alright temperatures, but I am the kind that prefer under 80C even if that means I am losing a bit of performance. I don't have a manual clock; Everything is on auto. I will try your settings later. Thank you
 

ojr10000o

Commendable
Aug 25, 2018
10
0
1,510
0
There is a Max Platform Thermal Limit setting. In my BIOS it's hidden until I enable PBO in Manual mode. Set that to 80C and you're done.

Ryzen monitors itself and limits voltage to maximum safe FIT values based on temperature but only so long as you leave the VCore voltage slider on AUTO. If you set it to a fixed value you're taking chances. You can use an offset to change it but positive offsets basically lie about the voltage it delivers when the processor asks for a certain voltage to be safe. That's dangerous too, so do it with as much caution as you would a fixed voltage.

BTW: I've read in several Reddit threads where AMD has stated that it's not unexpected to see temps upwards of 105C on 5900X's. It's kind of surprising to me and I've been looking for the actual thread where u/AMD_Robert (Robert Halleck, AMD tech. marketing engineer) says that and haven't found it yet. If anyone has a link, would sure be nice if you'd share it!

EDIT: I just duck-ducked it and found this: https://www.pcgamer.com/amd-views-ryzen-5000-cpu-temperatures-up-to-95c-as-typical-and-by-design/

I'm gonna go with 90C (for 5900's) now until I find that 105C reference. I think maybe some people might be confusing ryzen 5000 and RX-5700's. At any rate, I'd be more inclined to set a platform thermal limit of 90C than 80C if this is what Halleck is saying.
Will try it out. Thank you
 
Dec 15, 2020
5
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15
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Agree with Drea above. The best way to do what you suggest is to use the thermal limit. However, there will be significant throttling of the CPU clock speed as it hits/approaches this temp limit. It will likely hit this limit immediately with prime small FFTs unless you've incredible cooling. You'd be better served adjusting the PBO voltages manually to find a happy medium between amd/socket limits and the very high motherboard limits.

Edit: If you go down this route dont forget to also enable the single core offset - set it to 150/200. This will give you incredible single core performance boosts of upto 4.9ghz.
 
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..... However, there will be significant throttling of the CPU clock speed as it hits/approaches this temp limit. ...
You might be surprised how gentle the throttling is....

I was just running some tests to see if my AIO was still performing up to snuff (run a Prime95 with the fans off to see how long it takes the temp to start climbing) and was surprised when it hit 85C and just stopped there. With all core clocks fixed and steady I thought that was all the CPU was capable of by the algorithm and then I rememebered I had the platform thermal limit set at 85C. HAH...so back in BIOS and disable it and it went as high as 91C, with clocks about 100Mhz higher. It took an hour to climb that last 5 degrees and that's when I tapped out even though the rate of climb was still so low I couldn't track it.

Wow...240mm AIO's are great. Fans off and it still holds temp in check for an hour. Seriously, that's what liquid cooling is all about.
 
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Dec 15, 2020
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Hi. The throttling for me negatively impacted my Cinebench R23 scores back down towards those achieved on stock settings.

Yes the AIOs can be quite good - however my ML240L struggled with my PBO on max board settings. Best run the pump at max. I experimented incrementally dropping mine - got to a point where my idle temps jumped from 35 to 75 deg! It was just an experiment though as i'm pretty certain AIO pumps are meant to run at max. (12v?)
 
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...
Yes the AIOs can be quite good - however my ML240L struggled with my PBO on max board settings. Best run the pump at max
...
Indeed it will limit performance, after all I saw 100Mhz higher clocks at max load when I removed the thermal limit of 85C. But the throttling was gentle, not the sudden drop of clocks, as from 4.1Ghz to 3.2Ghz, that makes performance super glitchy. It just refused to go any faster than 4.0ghz once it got to 85C.

An AIO doesn't really mean it will keep your processor cooler, it just means it has enormous capacity to absorb heat before it saturates (the point where temp blooms out of control) because of the water volume used. Any air cooler, in contrast, saturates in seconds so fans have to be spinning fast right away (that's why Noctua's super quiet fans are so desireable.) So after my test I know I can keep fans at very low speeds and enjoy the quiet while knowing the CPU will stay under 90C even in a 2 hour handbrake encoding, or run a slightly louder profile and get a several hours more. BUT you're right: pump must always be at 100%. The truly bad AIO is one with a noisy pump, IMO.
 
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Reactions: ojr10000o
Dec 15, 2020
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Indeed it will limit performance, after all I saw 100Mhz higher clocks at max load when I removed the thermal limit of 85C. But the throttling was gentle, not the sudden drop of clocks, as from 4.1Ghz to 3.2Ghz, that makes performance super glitchy. It just refused to go any faster than 4.0ghz once it got to 85C.

So after my test I know I can keep fans at very low speeds and enjoy the quiet while knowing the CPU will stay under 90C even in a 2 hour handbrake encoding, or run a slightly louder profile and get a several hours more. BUT you're right: pump must always be at 100%. The truly bad AIO is one with a noisy pump, IMO.
That is precisely the performance I witnessed using the Temp. limit method. Not serious step change throttling but certainly enough to ruin my precious benchmarks.

I do like the quiet - I've all my fans pegged to my CPU temp sensor so virtually nothing happens until my CPU gets to 60 (just a bit of pump noise). Then its a gradual custom ramp.

Reversing my rear exhaust to become a filtered 140mm intake has markedly dropped CPU temps too. I've a top mounted AIO so this reversal brings in cool air regardless of what Mr GPU is upto down yonder. 200mm front intake takes care of the rest (everything 43degC or below).

This provides me some wriggle-room to up those PBO currents/voltages some more. I'm hitting 83C max on prime95 small FFT runs. 80 on Cinebench R23. 70C on Warzone and AC:Odyssey. All cores are hitting 4.6 Ghz on those benches too with the odd flutter upto 4.79 due to my offset. I'm only running a poor-mans 5600x though - not the big Daddy of the range.
 
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This provides me some wriggle-room to up those PBO currents/voltages some more. I'm hitting 83C max on prime95 small FFT runs.
...
Keep in mind that Prime95 stress tests run extremely, unrealistically well optimized AVX code on perfectly sized data sets in tightly nested loops. We are just not likely to ever see that kind of code perfection in real-world applications. CB23 is much more realistic even though it too is pretty well optimized. All I'm concerned with when running P95 is that it just not run up to 95C and hit the safety limits so I'm perfectly comfortable hitting mid-80's. So setting a thermal limit at 85C means real-world performance should never be affected..

The 3700X in my system never exceeds the low 70's in 'real world' work, and that includes handbrake encoding for several hours. Mid-upper 70's is about the point where the processor boost algorithm starts pulling back on clocks more heavily so that's a good spot for encoding.

And one thing many people don't keep in mind is the difference in temp readings: there's the spikey instantaneous reading in HWInfo, and then there's the AVERAGE reading. The temp spikes occurr when a core boosts to very high clocks and aren't thermally significant because the boost goes away pretty quickly and the spike ramps back down.

The average reading's the true indicator of processor thermal state but the spikey intantaneous temp reading is what the fan controllers follow on most motherboards. So that's why fans pulse if using a 'tight' fan profile. I loosen up the fan profile and use what an AIO brings to cooling. I don't start ramping fans until about 75C, that only to delay liquid saturation, but not really noticeable even then until 85C.
 
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