Playstation 5 [PS5] [Release November 12 2020]

[Karamazov]

playstathlon

 

[London Geezer]

I don’t know why they don’t just do it as www.pIaystation.com which would fool literally everyone until they click on it.

 

[Shifty Geezer]

April fools?

That's actually a good phishing scam. Reproduce the website, have some links, you'd probably get a lot of biters because the setup is so authentic looking.

 

[London Geezer]

I don’t know why they don’t just do it as www.pIaystation.com which would fool literally everyone until they click on it.

Then again I totally fell for it the last time. As we all remember. Idiot.

 

[Deleted member 11852]

Then again I totally fell for it the last time. As we all remember. Idiot.

Ha! It was that PS5 link that you posted a month or two back that made me pay close attention to this web address.

 

[Shifty Geezer]

Digital Foundry deep dive on Cerny's talk (Just posted - not read it yet)
https://www.eurogamer.net/articles/digitalfoundry-2020-playstation-5-the-mark-cerny-tech-deep-dive

 

[Strange]

Haha, 1 minute late to the party.
Just got the notification too

 

[BRiT]

DF intro to tease you to reading more... @ https://www.eurogamer.net/articles/digitalfoundry-2020-playstation-5-the-mark-cerny-tech-deep-dive

On March 18th, Sony finally broke cover with in-depth information on the technical make-up of PlayStation 5. Expanding significantly on previously discussed topics and revealing lots of new information on the system's core specifications, lead system architect Mark Cerny delivered a developer-centric presentation that laid out the core foundations of PlayStation 5: power, bandwidth, speed, and immersion. A couple of days prior to the talk going live, Digital Foundry spoke in depth with Cerny on the topics covered. Some of that discussion informed our initial coverage, but we have more information. A lot more.​

But to be clear here, everything in this piece centres on the topics in Cerny's discussion. There's much to assimilate here, but what you won't get are any further revelations about PlayStation 5 strategy - and it's not for want of asking. In our prior meeting back in 2016, Cerny talked in depth about how Sony was wedded to the concept of the console generation and the hardware revealed certainly attests to that. So is cross-gen development a thing for first-party developers? While stressing again that he's all in on the concept of console generations (as opposed to PC-style, more gradual innovation) he wasn't going to talk software strategy, and to be fair, that's not really his area.​

 

[Deleted member 7537]

Regarding CPU - GPU clocks and power budget.

In short, the idea is that developers may learn to optimise in a different way, by achieving identical results from the GPU but doing it faster via increased clocks delivered by optimising for power consumption. "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. That's what AMD calls SmartShift. There's enough power that both CPU and GPU can potentially run at their limits of 3.5GHz and 2.23GHz, it isn't the case that the developer has to choose to run one of them slower."

"There's another phenomenon here, which is called 'race to idle'. Let's imagine we are running at 30Hz, and we're using 28 milliseconds out of our 33 millisecond budget, so the GPU is idle for five milliseconds. The power control logic will detect that low power is being consumed - after all, the GPU is not doing much for that five milliseconds - and conclude that the frequency should be increased. But that's a pointless bump in frequency," explains Mark Cerny.

At this point, the clocks may be faster, but the GPU has no work to do. Any frequency bump is totally pointless. "The net result is that the GPU doesn't do any more work, instead it processes its assigned work more quickly and then is idle for longer, just waiting for v-sync or the like. We use 'race to idle' to describe this pointless increase in a GPU's frequency," explains Cerny. "If you construct a variable frequency system, what you're going to see based on this phenomenon (and there's an equivalent on the CPU side) is that the frequencies are usually just pegged at the maximum! That's not meaningful, though; in order to make a meaningful statement about the GPU frequency, we need to find a location in the game where the GPU is fully utilized for 33.3 milliseconds out of a 33.3 millisecond frame.

"So, when I made the statement that the GPU will spend most of its time at or near its top frequency, that is with 'race to idle' taken out of the equation - we were looking at PlayStation 5 games in situations where the whole frame was being used productively. The same is true for the CPU, based on examination of situations where it has high utilisation throughout the frame, we have concluded that the CPU will spend most of its time at its peak frequency."

Put simply, with race to idle out of the equation and both CPU and GPU fully used, the boost clock system should still see both components running near to or at peak frequency most of the time. Cerny also stresses that power consumption and clock speeds don't have a linear relationship. Dropping frequency by 10 per cent reduces power consumption by around 27 per cent. "In general, a 10 per cent power reduction is just a few per cent reduction in frequency," Cerny emphasises.

It's an innovative approach, and while the engineering effort that went into it is likely significant, Mark Cerny sums it up succinctly: "One of our breakthroughs was finding a set of frequencies where the hotspot - meaning the thermal density of the CPU and the GPU - is the same. And that's what we've done. They're equivalently easy to cool or difficult to cool - whatever you want to call it."

There's likely more to discover about how boost will influence game design. 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. It makes perfect sense as most game engines right now are architected with the low performance Jaguar in mind - even a doubling of throughput (ie 60fps vs 30fps) would hardly tax PS5's Zen 2 cores. However, this doesn't sound like a boost solution, but rather performance profiles similar to what we've seen on Nintendo Switch. "Regarding locked profiles, we support those on our dev kits, it can be helpful not to have variable clocks when optimising. Released PS5 games always get boosted frequencies so that they can take advantage of the additional power," explains Cerny.

Edit: Most of what I've read is nothing new. I haven't read the audio part yet.

 

[chris1515]

Regarding CPU - GPU clocks and power budget.



Edit: Most of what I've read is nothing new. I haven't read the audio part yet.

There is a bit more detail on the SSD and much more details on the audio part but many questions about the GPU features for example.

 

[BRiT]

So two key talking points on the CPU/GPU seems to be the same as before, questions around "most of the time":

"So, when I made the statement that the GPU will spend most of its time at or near its top frequency, that is with 'race to idle' taken out of the equation - we were looking at PlayStation 5 games in situations where the whole frame was being used productively. The same is true for the CPU, based on examination of situations where it has high utilisation throughout the frame, we have concluded that the CPU will spend most of its time at its peak frequency."​

...

There's likely more to discover about how boost will influence game design. 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. It makes perfect sense as most game engines right now are architected with the low performance Jaguar in mind - even a doubling of throughput (ie 60fps vs 30fps) would hardly tax PS5's Zen 2 cores. However, this doesn't sound like a boost solution, but rather performance profiles similar to what we've seen on Nintendo Switch. "Regarding locked profiles, we support those on our dev kits, it can be helpful not to have variable clocks when optimising. Released PS5 games always get boosted frequencies so that they can take advantage of the additional power," explains Cerny.​

 

[Strange]

Was the thermal density of CPU/GPU discussion before?

 

[Shifty Geezer]

So two key talking points on the CPU/GPU seems to be the same as before, questions around "most of the time":

"So, when I made the statement that the GPU will spend most of its time at or near its top frequency, that is with 'race to idle' taken out of the equation - we were looking at PlayStation 5 games in situations where the whole frame was being used productively. The same is true for the CPU, based on examination of situations where it has high utilisation throughout the frame, we have concluded that the CPU will spend most of its time at its peak frequency."​

...

There's likely more to discover about how boost will influence game design. 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. It makes perfect sense as most game engines right now are architected with the low performance Jaguar in mind - even a doubling of throughput (ie 60fps vs 30fps) would hardly tax PS5's Zen 2 cores. However, this doesn't sound like a boost solution, but rather performance profiles similar to what we've seen on Nintendo Switch. "Regarding locked profiles, we support those on our dev kits, it can be helpful not to have variable clocks when optimising. Released PS5 games always get boosted frequencies so that they can take advantage of the additional power," explains Cerny.​

I felt the rest of the interview, the bits that you chopped out, really explained that quite well. Why run your processor at full speed if its not doing anything? I doubt the real meaning of developer comments that they're 'throttling back'. If they are creating workloads that aren't using the CPU fully, then the CPU will be clocked lower because it doesn't need to run higher. That's very different from the devs choosing to throttle back to free up power for the GPU, or finding when they try to put what they want on the CPU, the GPU slows down.

Looks at this line:
"There's enough power that both CPU and GPU can potentially run at their limits of 3.5GHz and 2.23GHz, it isn't the case that the developer has to choose to run one of them slower."

If that's the case, the devs don't have to choose, then the line that devs are saying they are 'throttling back the CPU' is a misrepresentation of what's going on because they don't need to throttle.

Honestly, it sounds to me like Sony made a move for a more power-efficient hardware and now they're getting crucified for it! Like a US car company saying, "we changed from an inefficient 6 litre V8 to a super efficient 2 litre inline 6 that can generate the same BHP," and having customers up in arms that it's a gimped design.

 

[PSman1700]

So two key talking points on the CPU/GPU seems to be the same as before, questions around "most of the time":

"So, when I made the statement that the GPU will spend most of its time at or near its top frequency, that is with 'race to idle' taken out of the equation - we were looking at PlayStation 5 games in situations where the whole frame was being used productively. The same is true for the CPU, based on examination of situations where it has high utilisation throughout the frame, we have concluded that the CPU will spend most of its time at its peak frequency."​

...

There's likely more to discover about how boost will influence game design. 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. It makes perfect sense as most game engines right now are architected with the low performance Jaguar in mind - even a doubling of throughput (ie 60fps vs 30fps) would hardly tax PS5's Zen 2 cores. However, this doesn't sound like a boost solution, but rather performance profiles similar to what we've seen on Nintendo Switch. "Regarding locked profiles, we support those on our dev kits, it can be helpful not to have variable clocks when optimising. Released PS5 games always get boosted frequencies so that they can take advantage of the additional power," explains Cerny.​

Yes unfortenately we know nothing more then before.

 

[Pinstripe]

And at the nuts and bolts level, there are still some lingering question marks. Both Sony and AMD have confirmed that PlayStation 5 uses a custom RDNA 2-based graphics core, but the recent DirectX 12 Ultimate reveal saw AMD confirm features that Sony has not, including variable rate shading.

Hmm, RDNA1 feature set combined with RDNA2 clock-speeds then?

 

[Shifty Geezer]

Yes unfortenately we know nothing more then before.

"There's enough power that both CPU and GPU can potentially run at their limits of 3.5GHz and 2.23GHz, it isn't the case that the developer has to choose to run one of them slower."

 

[BRiT]

I felt the rest of the interview, the bits that you chopped out, really explained that quite well.

I agree, but that won't change what I see as the 2 talking points that will still be happening and focusing around the online discussions. That is for the sides that just want to present things in their own framing. They don't care about truth, they're just trying to score imagined points.

 

[BRiT]

"There's enough power that both CPU and GPU can potentially run at their limits of 3.5GHz and 2.23GHz, it isn't the case that the developer has to choose to run one of them slower."

And we did learn about locked profiles they can use only on devkits to assist in optimizing.

"Regarding locked profiles, we support those on our dev kits, it can be helpful not to have variable clocks when optimising. Released PS5 games always get bo​

 

[anexanhume]

A couple choice quotes here:

So, when I made the statement that the GPU will spend most of its time at or near its top frequency, that is with 'race to idle' taken out of the equation - we were looking at PlayStation 5 games in situations where the whole frame was being used productively. The same is true for the CPU, based on examination of situations where it has high utilisation throughout the frame, we have concluded that the CPU will spend most of its time at its peak frequency."

This is important to show they’re not gaming the metric.

Cerny also stresses that power consumption and clock speeds don't have a linear relationship. Dropping frequency by 10 per cent reduces power consumption by around 27 per cent.

This is a cubic relationship. 0.9^3 = 72.9%. That means drastic reductions in power. Downclocks should indeed be minor.

It's an innovative approach, and while the engineering effort that went into it is likely significant, Mark Cerny sums it up succinctly: "One of our breakthroughs was finding a set of frequencies where the hotspot - meaning the thermal density of the CPU and the GPU - is the same. And that's what we've done. They're equivalently easy to cool or difficult to cool - whatever you want to call it."

This is also an important point. Some Intel desktop CPUs run faster than their integrated graphics-less counterparts because those idle graphics cores actually add as a thermal spreader. If you had uneven thermal density, they’d be contributing to each other’s hot spots.

There's likely more to discover about how boost will influence game design. 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. It makes perfect sense as most game engines right now are architected with the low performance Jaguar in mind - even a doubling of throughput (ie 60fps vs 30fps) would hardly tax PS5's Zen 2 cores. However, this doesn't sound like a boost solution, but rather performance profiles similar to what we've seen on Nintendo Switch. "Regarding locked profiles, we support those on our dev kits, it can be helpful not to have variable clocks when optimising. Released PS5 games always get boosted frequencies so that they can take advantage of the additional power," explains Cerny.

Yes, developers already see dropped clocks, but it’s intentional. Some PC benchmarking sites tear their hair out trying to interpret benchmark results because of unpredictable boost behavior. This eliminates that.

"All of the game logic created for Jaguar CPUs works properly on Zen 2 CPUs, but the timing of execution of instructions can be substantially different," Mark Cerny tells us. "We worked to AMD to customise our particular Zen 2 cores; they have modes in which they can more closely approximate Jaguar timing. We're keeping that in our back pocket, so to speak, as we proceed with the backwards compatibility work."

This is the subject of several of Cerny’s patents.

GPUs process hundreds or even thousands of wavefronts; the Tempest engine supports two," explains Mark Cerny. "One wavefront is for the 3D audio and other system functionality, and one is for the game. Bandwidth-wise, the Tempest engine can use over 20GB/s, but we have to be a little careful because we don't want the audio to take a notch out of the graphics processing. If the audio processing uses too much bandwidth, that can have a deleterious effect if the graphics processing happens to want to saturate the system bandwidth at the same time."

This is very important. It gives us an upper bound for how much memory bandwidth we would want on a per CU basis. Since the clock is the same as the GPU, PS5’s number is 720GB/s.

As a result, with the GPU if you're getting 40 per cent VALU utilisation, you're doing pretty damn well. By contrast, with the Tempest engine and its asynchronous DMA model, the target is to achieve 100 percent VALU utilisation in key pieces of code."

This shows just how little of a system’s teraflops can be realistically used. 40% VALU usage!

 

[PSman1700]

"There's enough power that both CPU and GPU can potentially run at their limits of 3.5GHz and 2.23GHz, it isn't the case that the developer has to choose to run one of them slower."

That still doesn’t clear things up regarding the lowest clocks for either gpu or cpu (or both simultaniously).
Potentionally they can run at those speeds, as advertised.
Developers dont get to choose, of which to run slower, it probably is automatic with this smartshift tech, it probably had to do with profiling. Alex from DF explained this before here. Like i said nothing new.