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Undervolting Ryzen 5000 series

GoogalyMoogaly

GoogalyMoogaly

GoogalyMoogaly

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So I've just got a Ryzen 5 5500 for my SFF PC. Cooling is limited (Noctua NH-L9a) and when running Cinebench 20 it was hitting 95ºC (Now admittedly I don't plan do play a lot of Cinebench, but may do a little video encoding from time to time).
So I'd like to bring the heat down and I'm thinking the best way to do that is to undervolt, right?

So what's the best way to do that with a 5500?
Looking around I see lots of people suggesting PBO, which seems simple but also -30 (or whatever) doesn't seem like it's reducing the voltage that much (given that it seems to be hitting 1.3-1.35V).
I've also seen suggestions saying to just set the Vcore manually.

Do people do this in the BIOS or do they use Ryzen Master? Last time I used that it was a bit nasty and didn't seem to do much, but I guess it may have changed.
 
Curve optimiser. Set your PBO to whatever you want then set - 30 and run your cycler to rest for stability, and adjust settings from in windows using a tool that comes with it, until you get stable.
 
MyBrainz said:
Negative Offset on Vcore in BIOS.. I have -0.1000v with my 5800X3D which has brought temps down a lot while still hitting 4450Mhz on all core.

Start with -0.0500v and test from there.
Click to expand...
My motherboard doesn't seem to offer offset voltage as an option, once you set overclocking to Manual you have to set the specific values for clock and voltage.

alec said:
the best way is to lower the thermal limit from 95 to whatever is comfortable for you
and THEN to recover most of performance do curve optimizer
Click to expand...
I set the thermal limit to 85ºC and that seems pretty good at keeping it under 90ºC (It went to 86ºC, so might up it a degree or two).

Ch3m1c4L said:
Curve optimiser. Set your PBO to whatever you want then set - 30 and run your cycler to rest for stability, and adjust settings from in windows using a tool that comes with it, until you get stable.
Click to expand...
Not sure what you mean by "Set your PBO to whatever", but I did set -30 all core and it seemed fine. Won't let me go any lower than -30.

As expected Cinebench scores are down slightly but I can live with it if I don't have to worry about it running too hot (I think 90ºC is the limit for a 5500?).
 
PBO Tuner2 might let you go lower than -30, can't recall if it does or just tells you it has but only goes to -30. To be fair that should give you a good bit of extra headroom.

If you set a thermal limit then have you checked if it's just constantly throttling? If so then maybe just let it handle itself (?)
Ryzen master will do some auto curve optimizer stuff but I was never convinced it did it 'properly' - I have no evidence for this claim.
 
Rob_B said:
PBO Tuner2 might let you go lower than -30, can't recall if it does or just tells you it has but only goes to -30. To be fair that should give you a good bit of extra headroom.

If you set a thermal limit then have you checked if it's just constantly throttling? If so then maybe just let it handle itself (?)
Ryzen master will do some auto curve optimizer stuff but I was never convinced it did it 'properly' - I have no evidence for this claim.
Click to expand...
It's only throttling when it hits the limit (85ºC), but yeah, at that point it is constantly throttling (a little).

I've seen some stuff online saying to avoid Ryzen Master as it can cause issues. I'm not sure what more it could do anyway if the BIOS won't let me go below -30. If I could go below -30 or if it didn't seem stable at -30 then something that could automatically find reasonable values might be useful.
 
-30 is free limit on these cpus. It is not an exact value, it is the magnitude of the undervolt. If you want lower, set the core voltage itself to be lower.

What I meant by set your PBO to whatever, was to set your wattage, amp and temp limits for its auto boosting to whatever you, personally, decide you want them to be, then to do curve optimiser after that. You can also turn this off, and it'll run within it's normal tdp, boost less aggressively but run much, much cooler. Unless ofc you've already got it turned off.
 
GoogalyMoogaly said:
It's only throttling when it hits the limit (85ºC), but yeah, at that point it is constantly throttling (a little).

I've seen some stuff online saying to avoid Ryzen Master as it can cause issues. I'm not sure what more it could do anyway if the BIOS won't let me go below -30. If I could go below -30 or if it didn't seem stable at -30 then something that could automatically find reasonable values might be useful.
Click to expand...
My thought was, if its throttling anyway just let it decide when to do so rather than setting an arbitrary limit?
I assume you've repasted and set fan curves? My first thoughts on reading a 5500 hitting 95C was "no way, how bad do you mess up to hit that?!"
 
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Rob_B said:
My thought was, if its throttling anyway just let it decide when to do so rather than setting an arbitrary limit?
I assume you've repasted and set fan curves? My first thoughts on reading a 5500 hitting 95C was "no way, how bad do you mess up to hit that?!"
Click to expand...
I've not repasted, but it was much the same on the old CPU (Ryzen 1400) and when I took the cooler off the coverage looked fine. I have set fan curves though.
I think it's just a limited cooler in a case with no airflow. You can feel it blowing hot air, so it's not like the heatsink isn't getting hot.
 
alec said:
the best way is to lower the thermal limit from 95 to whatever is comfortable for you
and THEN to recover most of performance do curve optimizer
Click to expand...

this, i did it with a 5800x that would game at 88c

set a max limit of 75c, max power draw of 85w and curve optimizer of -21(max i could get)
 
Are you sure you are putting in a negative 30 value on curve optimizer and not positive by mistake? Each step of CO is somewhere between 3-5mV so a setting of -30 is significant, and should at least be noticeable.
 
A quick Google suggests 3-5mv per increment (but I can't find a proper source as I've not looked much) so that'd be 90-150mv reduction so about in the right ballpark.
 
ATIorNvidia said:
If that's still not enough then manually setting voltage/frequency is what I'd do. With a slight underclock (say 4ghz or 4.1) you'd be able to retain more all core performance than if you set a temp limit.
Click to expand...
Surely that depends on if I hit thermal limit or not? Since the only thing that's caused it to hit 95ºC (so far, limited testing at this point) is running Cinebench 20/23/24, I figure other things might benefit from not underclocking. I'm actually even thinking about whether it's worth trying to increase the max clock to boost performance while it's not thermal throttling (during Cinebench run it seemed to drop about 150mhz to 4100mhz and droped the VCore to 1.16 to keep it at around 86ºC until the Cinebench run finished).
 
my 5600G
-2 (offset units in pbo) anything more in the negative offset direction isnt stable.
hits 4.45GHz boost
1.3ishV max (cine R23)
set 67C thermal limit, which it hits in cinebench. also tried 72C limit which it also hits in R23. iirc i get ~10k pts in r23. the 5600G is limited to pcie 3.0, had it for a couple of years, old b450 mobo died. have a new b550. works ok.
 
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GoogalyMoogaly said:
Surely that depends on if I hit thermal limit or not? Since the only thing that's caused it to hit 95ºC (so far, limited testing at this point) is running Cinebench 20/23/24, I figure other things might benefit from not underclocking. I'm actually even thinking about whether it's worth trying to increase the max clock to boost performance while it's not thermal throttling (during Cinebench run it seemed to drop about 150mhz to 4100mhz and droped the VCore to 1.16 to keep it at around 86ºC until the Cinebench run finished).
Click to expand...
Yeah, but I was under the assumption you wanted to eliminate throttling altogether without setting a limit yourself. If you are happy with the 85C limit then just keep it there.

Increasing the boost clock with PBO will negatively affect CO stability and probably increase temps more, may or may not work depending on if you have a good sample.
 
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ATIorNvidia said:
Yeah, but I was under the assumption you wanted to eliminate throttling altogether without setting a limit yourself. If you are happy with the 85C limit then just keep it there.

Increasing the boost clock with PBO will negatively affect CO stability and probably increase temps more, may or may not work depending on if you have a good sample.
Click to expand...
I mean it'd be nice to eliminate the throttling if I could. That said, downclocking due to throttling will only affect it when it hits the limit but underclocking will affect it regardless. I guess the question is how much throttling will downclock it and how much I'd have to downclock it to get it to not throttle.
I guess I'll need to see how it goes and how often it throttles. Did some x265 video encoding and I don't think it even hit 80ºC and I don't imagine too much gaming will push it that hard. I can live with it throttling in just Cinebench if that's the only place it does it. But it's early days so I'll need to see how often it does throttle.

It's a small cooler in a SFF case with no airflow (other than that created by the CPU cooler) so I'm expecting it to run hot, I was just hoping it wouldn't be 90ºC+ hot.
 
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