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Balancing clocks for max power draw is a different animal than variable clock throttling

Clandsiota

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Several developers speaking to Digital Foundry have stated that their current PS5 work sees them throttling back the CPU in order to ensure a sustained 2.23GHz clock on the graphics core.
The CPU and GPU each have a power budget, of course the GPU power budget is the larger of the two," adds Cerny. "If the CPU doesn't use its power budget - for example, if it is capped at 3.5GHz - then the unused portion of the budget goes to the GPU.

so, instead of cooling, it’s based on power usage/budget.
 

CerealBro1

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Yeah, I am honestly really curious how it will hold up in terms of temperature and how often it will actually sit at those boost clocks. My game room is upstairs and can get pretty warm during the summer, so am I just going to have to accept poorer frame rates as the system will be unable to keep a stable clock? Or will my console stay at those clocks and get all toasty? And then they talked about having a "Master APU" or whatever they called it that they are using to profile the clock variation of all chips but how will they ensure that every chip will hold up to those clocks exactly the same way?

I feel like they would have been better using locked clocks like every other console
 

Max_Po

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“Variable clocks” is a term used when top clock speeds get throttled due to heat. That can be unpredictable depending on the user’s local weather, etc. That can be difficult to optimize games for. 100% Predictably balancing clocks for max power draw is a different animal.
PS5 comes with an animal.. you heard it here ...
 
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DForce

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Yeah, I am honestly really curious how it will hold up in terms of temperature and how often it will actually sit at those boost clocks. My game room is upstairs and can get pretty warm during the summer, so am I just going to have to accept poorer frame rates as the system will be unable to keep a stable clock? Or will my console stay at those clocks and get all toasty? And then they talked about having a "Master APU" or whatever they called it that they are using to profile the clock variation of all chips but how will they ensure that every chip will hold up to those clocks exactly the same way?

I feel like they would have been better using locked clocks like every other console

The PS5 won't throttled based temperature. All PlayStation 5 consoles will run the same.

He's saying they can predictably balance the clocks since it's based on workload and not temperature.
 
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So he's saying hot environments will impact the clocks because I thought it was generally accepted that wouldn't be the case? Granted, this same guy has also been a source for other PS5 info I've seen quite a few unquestionably take as truthful; what he's saying in this instance doesn't sound particularly great for PS5's variable frequency strategy so I'd be interested to see if those same types still take his word or somehow find ways to argue against them this time xD.

My personal opinion? Variable frequency was always going to be a bit of a pain no matter how they went about doing it. The approach just demands more micromanagement on the side of the developer. Needing to make sure they know what power consumption their code will likely draw to ensure clock ranges are kept to a spec that won't end up resulting in excess use that can produce excess heat and thus requiring a reduction in power resulting in a reduction of clock frequency...yeah that's going to complicate things no matter how you look at it.

It's being suggested that Sony have some logic on the APU to "automatically" handle power load shifting within 2 Ms, but how exactly does that part of the design even work? How is it determining when to adjust power? Do devs need to write triggers in their code to signal "hey, this is probably going to draw up a lot of power so start reducing the power load on Event X okay?", because that require developer's direct input. And it wouldn't be automatic in the sense of requiring no dev input the way it's been suggested.

If that silicon is doing the detection automatically, I guess it could be using a type of sensor with a microprocessor or microcontroller unit built into it. Has to be able to detect the currents, so I guess it'd need to be integrated into the PSU, but that will complicate the PSU design in both engineering and costs. And I can't imagine that type of sensor capability (if it requires no developer input) to be on the cheap, not if they want quality.
 

Keihart

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Yeah, I am honestly really curious how it will hold up in terms of temperature and how often it will actually sit at those boost clocks. My game room is upstairs and can get pretty warm during the summer, so am I just going to have to accept poorer frame rates as the system will be unable to keep a stable clock? Or will my console stay at those clocks and get all toasty? And then they talked about having a "Master APU" or whatever they called it that they are using to profile the clock variation of all chips but how will they ensure that every chip will hold up to those clocks exactly the same way?

I feel like they would have been better using locked clocks like every other console
The tweet it's stating the complete opposite of what you are writing.
Since it's based on power management, your hot room shouldn't affect much the console, at least, it should be less of a problem than with PS4 for example.
 

Hobbygaming

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Interesting tweet. And this guy would know what he's talking about

Either way, Sony are smart they have great engineers and Mark Cerny the system architect is a genius, they'll figure it out and keep coming with the bangers 🔥
 
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ANIMAL1975

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So he's saying hot environments will impact the clocks because I thought it was generally accepted that wouldn't be the case? Granted, this same guy has also been a source for other PS5 info I've seen quite a few unquestionably take as truthful; what he's saying in this instance doesn't sound particularly great for PS5's variable frequency strategy so I'd be interested to see if those same types still take his word or somehow find ways to argue against them this time xD.

My personal opinion? Variable frequency was always going to be a bit of a pain no matter how they went about doing it. The approach just demands more micromanagement on the side of the developer. Needing to make sure they know what power consumption their code will likely draw to ensure clock ranges are kept to a spec that won't end up resulting in excess use that can produce excess heat and thus requiring a reduction in power resulting in a reduction of clock frequency...yeah that's going to complicate things no matter how you look at it.

It's being suggested that Sony have some logic on the APU to "automatically" handle power load shifting within 2 Ms, but how exactly does that part of the design even work? How is it determining when to adjust power? Do devs need to write triggers in their code to signal "hey, this is probably going to draw up a lot of power so start reducing the power load on Event X okay?", because that require developer's direct input. And it wouldn't be automatic in the sense of requiring no dev input the way it's been suggested.

If that silicon is doing the detection automatically, I guess it could be using a type of sensor with a microprocessor or microcontroller unit built into it. Has to be able to detect the currents, so I guess it'd need to be integrated into the PSU, but that will complicate the PSU design in both engineering and costs. And I can't imagine that type of sensor capability (if it requires no developer input) to be on the cheap, not if they want quality.
Someone didn't read this correctly.
 

Thugnificient

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So he's saying hot environments will impact the clocks because I thought it was generally accepted that wouldn't be the case? Granted, this same guy has also been a source for other PS5 info I've seen quite a few unquestionably take as truthful; what he's saying in this instance doesn't sound particularly great for PS5's variable frequency strategy so I'd be interested to see if those same types still take his word or somehow find ways to argue against them this time xD.

My personal opinion? Variable frequency was always going to be a bit of a pain no matter how they went about doing it. The approach just demands more micromanagement on the side of the developer. Needing to make sure they know what power consumption their code will likely draw to ensure clock ranges are kept to a spec that won't end up resulting in excess use that can produce excess heat and thus requiring a reduction in power resulting in a reduction of clock frequency...yeah that's going to complicate things no matter how you look at it.

It's being suggested that Sony have some logic on the APU to "automatically" handle power load shifting within 2 Ms, but how exactly does that part of the design even work? How is it determining when to adjust power? Do devs need to write triggers in their code to signal "hey, this is probably going to draw up a lot of power so start reducing the power load on Event X okay?", because that require developer's direct input. And it wouldn't be automatic in the sense of requiring no dev input the way it's been suggested.

If that silicon is doing the detection automatically, I guess it could be using a type of sensor with a microprocessor or microcontroller unit built into it. Has to be able to detect the currents, so I guess it'd need to be integrated into the PSU, but that will complicate the PSU design in both engineering and costs. And I can't imagine that type of sensor capability (if it requires no developer input) to be on the cheap, not if they want quality.
He's just saying the PS5 aims to balance clocks for max power draw and that it's very different from the traditional method of clocks throttling based on temps.

I understand the confusion.
 

93xfan

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I mean.. if the clocks are variable, the clocks are variable.

Sony's solution is just different; while he has a point he's being a bit silly with the language here.
I think there is a point to this. Developers know what to expect and can optimize it better as a result.
 
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LordOfChaos

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I mean.. if the clocks are variable, the clocks are variable.

Sony's solution is just different; while he has a point he's being a bit silly with the language here.
It's not just playing with language, it's pointing out that it's completely deterministic and code will run the same way every time, unlike PC turbo boosts.

So it does vary in clock speed, but not in what it does in consecutive runs.

We already knew that so not really saying anything new.
 
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Bryank75

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'Software engineer'...... 'Roblox'..... GTFO!

There is far too much focus on the stupid tflop number... look what studios did on 1.8 tflops this generation. I am not worried about it, at all.
I am not buying a next gen console... I am buying a next gen PlayStation, that is what I am interested in. There is no alternative.
 

Thugnificient

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He shouldn't have said this because, looking at the responses, even the most verbose idiot on this forum needs to work on his comprehension.
“Variable clocks” is a term used when top clock speeds get throttled due to heat. That can be unpredictable depending on the user’s local weather, etc. That can be difficult to optimize games for. 100% Predictably balancing clocks for max power draw is a different animal.

He should have said this for the second phrase:

"Being able to predict with 100% reliability how to balance clocks with power draw is a different animal than the aforementioned variable clocks."

Dude needs to work on his syntax and punctuation.
 
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Thanks for having no input to contribute. That's fantastic (y)

He's just saying the PS5 aims to balance clocks for max power draw and that it's very different from the traditional method of clocks throttling based on temps.

I understand the confusion.
If that's the case he really isn't saying anything most of us haven't already figured out for ourselves. At this point I want to know how exactly are they balancing the clocks for max power draw...without developer input. Either it's being handled with some sensor/microcontroller logic in a customized PSU running some code that detects what component is access how much power and for how long, triggering adjustments from there....

....or developers are in fact needing to put some conditional code into it on their end, meaning they have to know ahead of time what type of power load scenario they expect sections of their code will produce. It's one of those two options, and both come at a cost in one way or the other.
 
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dano1

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I always understood that the PS5 could run at full speed if it needed too 24/7. But the variable part was when it did need the power it would clock dow to save electricity? And that would be 95% of the time.
 
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ANIMAL1975

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It's a completely different paradigm," says Cerny. "Rather than running at constant frequency and letting the power vary based on the workload, we run at essentially constant power and let the frequency vary based on the workload."

An internal monitor analyses workloads on both CPU and GPU and adjusts frequencies to match. While it's true that every piece of silicon has slightly different temperature and power characteristics, the monitor bases its determinations on the behaviour of what Cerny calls a 'model SoC' (system on chip) - a standard reference point for every PlayStation 5 that will be produced.
"Rather than look at the actual temperature of the silicon die, we look at the activities that the GPU and CPU are performing and set the frequencies on that basis - which makes everything deterministic and repeatable," Cerny explains in his presentation. "While we're at it, we also use AMD's SmartShift technology and send any unused power from the CPU to the GPU so it can squeeze out a few more pixels."
Source
Max is saying the exact opposite of what you wrote thicc_girls_are_teh_best thicc_girls_are_teh_best hope you have already come to that conclusion
Devkits have fixed clocks so that devs have no extra work optimizing for the game _ we know this since ps5 reveal in March, and also that there is custom hardware, the Power Control Unit, managing the intire process.
Next time do some research before the wall of text.
 
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LordOfChaos

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I always understood that the PS5 could run at full speed if it needed too 24/7. But the variable part was when it did need the power it would clock dow to save electricity? And that would be 95% of the time.
Not exactly, they said the worst case scenarios can force the clocks down, but that dropping "only a few percent" tamps down power by 10%. Like AVX CPU code is particularly power hungry. But also that it would stay near the peak clocks most of the time.

The point of all this is to keep the power output in wattage of the APU steady depending on the mix of the workload coming through the CPU and GPU, fixed power instead of fixed clocks, which lets both parts have the potential to be clocked higher than they otherwise would have.

This is not like PC turbo boost, which is thermally opportunistic and goes beyond TDP momentarily, and can vary based on heat, this instead makes sure the power use is steady which makes it deterministic run to run.
 

Aidah

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We already know from the hardware presentation that it's not based on temperature but instead on power draw and therefore predictable, consistent and unaffected by the environment. This isn't news, he's just reiterating.

Some of these replies... work on your comprehension.
 
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LazyParrot

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As we all know, PS5 can't handle maxing out its cpu and gpu clocks 100% of the time. If it could, it would and you wouldn't need variable rates.
Yes you would, unless you love wasting energy. Why would you want your GPU and CPU to run at their maximum clock speed if whatever you're doing doesn't require it? I could force the CPU and GPU in my PC to boost at all times, but why would I want to?
 

splattered

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What we need is an actual detailed hardware breakdown like we've had with the Series X.

Also we could use CURRENT HW/SW Sony engineers giving talks about the nuances of the console.

Very weird that we haven't had either yet... it's not that far from launch.

Too many questions. Feels like smoke and mirrors/bait and switch at this point.