Next Generation Hardware Speculation with a Technical Spin [post GDC 2020] [XBSX, PS5]

Discussion in 'Console Technology' started by Proelite, Mar 16, 2020.

  1. MrFox

    MrFox Deludedly Fantastic
    Legend Veteran

    Joined:
    Jan 7, 2012
    Messages:
    6,485
    Likes Received:
    5,990
    They were not hitting a power wall, they never said that. It was causing cost/performance issues. They can make a 1000W console any time they want if they have no cost limit on the cooling. It's about the balancing act of where to invest a limited BOM.
     
    Mitchings likes this.
  2. shiznit

    Regular Newcomer

    Joined:
    Nov 27, 2007
    Messages:
    338
    Likes Received:
    88
    Location:
    Oblast of Columbia
    I get what you're saying but it still doesn't make sense to me, unless you're referring to absolute worst corner case. Say clocks of 2.0/3.0 were consuming 200W under typical load, how is 98% of 2.23/3.5 going to consume less? They are claiming to be able to sustain higher clocks than the fixed version.
     
    Janne Kylliö, blakjedi and VitaminB6 like this.
  3. MrFox

    MrFox Deludedly Fantastic
    Legend Veteran

    Joined:
    Jan 7, 2012
    Messages:
    6,485
    Likes Received:
    5,990
    Yes, and he explains why the average is higher than a fixed clock, because they don't have to design the entire power delivery and cooling system just for the massive outlier peaks, which may or may not even happen. The normal gaming demand however is "most of the time".

    It's about averages, and peak being crazy exponential outliers.

    We have the same thing on gpus with "gaming clocks" which are much higher than the guaranteed base clock. If you have to guarantee any sequence at a fixed clock, you have to use the base clock. Which is what ps4/xb1 mostly did.
     
    Mitchings, KeanuReeves and goonergaz like this.
  4. 3dilettante

    Legend Alpha

    Joined:
    Sep 15, 2003
    Messages:
    8,365
    Likes Received:
    3,955
    Location:
    Well within 3d
    That might be one way to make clocks more predictable, or perhaps given what we know about the power delivery for the Series X that means Sony's console may run at lower consumption.
    There are also other ways to reduce consumption that are like throttling clocks, like instruction issue limits or warm-up periods. Duty cycling could keep the "fixed clock" even though it halts some activity on a routine basis.

    We'd need to know more about the hot-spot properties of the chip and process, and the ability of the chip and board to deliver adequate power. The power-based modeling and Vdroop compensation AMD has can make some of these problems more readily handled, especially since temperature-based tracking can lag too much at these scales, whereas activity counters or voltage drop can highlight high consumption in a handful of cycles.

    It's possible that Sony pulled an AMD and left voltages higher than necessary for many of its chips. In that scenario, having a dynamic clock method like AMD's can enable higher consumption than would be possible otherwise, since some of the chips that need the higher voltage could have failed more stringent limits. I think Sony would want a better handle on power consumption, but then again if their choice in CU count forced them to higher clocks--which the clocking method makes possible--then they might be worse off in terms of overall power than they would have been otherwise.


    Cerny outlined a scenario where the question was whether they would bind the platform clocks to what they estimated was the worst-case consumption scenario. The kinds of operations and the overall utilization can wildly change power consumption, and the designers would need to make a prediction about all the software the chip would ever run, and hope they guessed right.
    Should a design cap its frequencies at a level that is safe for some worst-case they cannot predict, and what can they do if they guess wrong. A clocking method that instead catches when they meet a high-consumption scenario and allows higher clocks at all other times would be tempting.
     
    TheAlSpark and Mitchings like this.
  5. shiznit

    Regular Newcomer

    Joined:
    Nov 27, 2007
    Messages:
    338
    Likes Received:
    88
    Location:
    Oblast of Columbia
    They could have still throttled under 2.0/3.0 for the outliers, I'm not referring to the benefits of a power cap, I get that. What doesn't make sense is their claim of sustained clocks above 2.0/3.0 using less power than 2.0/3.0 fixed.
     
  6. goonergaz

    Veteran

    Joined:
    Jun 3, 2005
    Messages:
    3,601
    Likes Received:
    1,041
    I don’t get the excitement over the CPUs, to be honest I’m disappointed- last gen CPUs were criticised for being too weak so 5x isn’t much of an upgrade.

    Groundhog Day! I guess we just have to wait for me details from Sony.
     
    VitaminB6 likes this.
  7. Kaotik

    Kaotik Drunk Member
    Legend

    Joined:
    Apr 16, 2003
    Messages:
    9,125
    Likes Received:
    3,014
    Location:
    Finland
    Zen 2 is pretty much the most powerful x86-architecture/implementation out there at the moment, I don't know how anyone could have really asked for more on these consoles. 16 cores?
     
  8. PSman1700

    Veteran Newcomer

    Joined:
    Mar 22, 2019
    Messages:
    2,684
    Likes Received:
    895
    Probably Zen 3 :p I think we should be really happy a 8 core 16 thread CPU running at close to 4ghz in a console. Powerfull GPU's and and SSDs, i think games designed with that in mind will be amazing on every level.
     
    CeeGee, scently and KeanuReeves like this.
  9. Rurouni

    Veteran

    Joined:
    Sep 30, 2008
    Messages:
    977
    Likes Received:
    274
    Do they claim that?
    If they do, it might be about the possibility of one game to run at higher clock while using less power vs another game that run at lower clock but using more power. For an extreme example, God of War probably will use more power at 2.0/3.0 vs Minecraft at 2.23/3.5. With a fixed clock you're basically leaving extra performance on the table because not all of the games will be able to work the CPU and GPU as hard as God of War.

    Of course you can design a system with a fixed clock that will not overheat even under extreme load, like fixing it to a lower clock or using a more potent cooling. You'll get a system that potentially can perform better but running slower to account for the peak or a system that rarely use its cooling system at max capacity or something in between that.

    What I'm curious about is why MS doesn't use variable clockspeed since arguably they are a more PC centric company and since PC games doesn't mind variable clockspeed, why they chose a fixed speed? It probably does make it easier for a dev since they have less thing to worry about, but then they need to make (at least for a year?) their game run on XsX and XO. Also considering how much Xbox exclusives are actually only console exclusive (available on PC even for MS own games), if you ask me which company will embrace variable clockspeed first, I will answer MS.
     
  10. dobwal

    Legend Veteran

    Joined:
    Oct 26, 2005
    Messages:
    5,431
    Likes Received:
    1,486
    The clocks are basically fixed except with certain caveats. I think they just used horrible language when they used the term “boost”.

    Imagine buying a PS4 Pro with a chip that barely passed QA/QC and is prone to power leakage. Every time you play a gpu intensive game it whines like a jet engine.

    The PS5 solution for such a chip is not to let it wind up the fans to such high levels. The console will back down the frequency of its cpu/gpu to compensate and lower the fps of the game to compensate.

    It’s not a given that all PS5s will need to downclock as chips across a wafer will have different power characteristics. Some will handle 2.23 and 3.5 GHz more readily than others as they won’t need as much power to sustain those clocks.
     
    #1310 dobwal, Mar 29, 2020
    Last edited: Mar 29, 2020
  11. KeanuReeves

    Newcomer

    Joined:
    Sep 30, 2017
    Messages:
    59
    Likes Received:
    27
    We have been through this one a few times now :mrgreen: Fixed 2.0/3.0 is just a hypothetical. If they keep it there fixed then the outlier scenarios would just need a slightly bigger fan and powersupply to manage it (at the cost of fan noise). But with the variable frequency they can have higher clocks that drop when power hungry instructions are used too much. That means they don't need to have a bigger power supply and they don't need to have a bigger fan. They just drop the frequency by a few points.
     
    goonergaz and Mitchings like this.
  12. Rockster

    Regular

    Joined:
    Nov 5, 2003
    Messages:
    973
    Likes Received:
    129
    Location:
    On my rock
    So many issues being conflated. Hopefully, some of you find this helpful.

    1) There are other constraints that limit the maximum frequency a part can run at besides heat and power. Ultimately you'd be limited by the speed of the transistors and wiring delays. So the chip design and physical signalling components impose hard limits. Please don't think console manufacturers plan clocks around power supply and cooling solution budgets. Everything they do in that regard is within a predetermined window.

    2) The PS5 implementation of variable clocks essentially ignores temperature. Sony has set a console standard, or "model", as they refer to it, where typical PS5's are placed in what I'd assume to be a sort of worst-case cooling environment and tested. They then measure the max power draw at which their cooling solution meets their reliability and acoustic thresholds. The result of this testing established a fixed maximum power rating for their SoC which is to be applied to all PS5's regardless of the actual temperature each might run at. So if person A is running their PS5 in a freezer and person B is in the desert, both will have the same power limit imposed.

    3) Power draw changes with frequency and load. I think this is causing the most confusion. Processors (CPU and GPU), even when running at their maximum configured clock speed, will draw relatively little power if the majority of its execution units are idle. So even at fixed clock speeds, sitting in a menu doing nothing will draw less power and in turn, run cooler then while in a busy game scenario. Processors are massively parallel units, meaning they can execute lots of operations concurrently. For example, every CU in the GPU is technically able to carry out 128 concurrent operations each clock cycle. Applications, such as games, vary on how effectively they can utilize all the available compute components within a processor simultaneously. As programmers optimize their code and data so the processor can utilize greater and greater amounts of its available compute concurrently, the processing load, and in turn power draw, increases. At some computational utilization threshold (load), the application would reach the defined power limit. In order to be able to concurrently utilize all its available compute and still be under Sony's previously defined power ceiling, the PS5 reduces clock speeds to compensate for that load.

    4) Sony has said, when the CPU and GPU aren't being fully utilized, they can run up to 3.5GHz and 2.223 GHz respectively. And that at higher loads, they will run at lower (as of yet undisclosed) clock-speeds. The only sense we have for clock-speeds in a hypothetical 100% load scenario across the entire SOC, are Cerny's comments that 3GHz on the CPU "was causing headaches" and 2GHz on the GPU "was looking like an unreachable target". As 100% utilization across the entire SoC in a practical sense is not possible just due to the inherent inefficiencies of real-world code. data sets, and compute requirements; the expectation Sony has is that they will run at or near the max clocks much of the time.
     
    egoless, Tsaki, ToTTenTranz and 13 others like this.
  13. temesgen

    Veteran Regular

    Joined:
    Jan 1, 2007
    Messages:
    1,649
    Likes Received:
    454
    I think this is a bigger hint than many are realizing.

    We may care about frame rates north of 30, but the average gamer doesn't. Sony may very well have designed the PS5 to be able to generate 4k with a little additional headroom and focused the overall design around actually providing the developers with tools to make game design without all the legacy requirements mechanical drives and legacy sound applications limits their work to.

    Immersion has more to do less waiting around and more vivid sound once the graphics get to a certain point.

    VR can add to that immersion too but they may see it as a niche market until there is significant improvement with the controls, dual game development (vr and conventional) and cost reductions. If that's the case, they don't need a GPU capable of 120 fps.


    RTRT remains an open question but the Sony developer comment on Twitter may hint at Ray tracing this generation being a fundamentally limited application in a practical sense and if it adds significant cost why bother?

    A cheaper machine pumping out beautiful 4k images with great texture and sound and essentially no loading could be the right answer. Of course if the cooling solution adds significant cost or the dynamic clocks adds BC issues migrating to PS6, it will be a mistake.
     
    PSman1700 likes this.
  14. DSoup

    DSoup meh
    Legend Veteran Subscriber

    Joined:
    Nov 23, 2007
    Messages:
    12,735
    Likes Received:
    8,122
    Location:
    London, UK
    YouTube does transcribing for most videos. Click the three dots (". . .") under the video then Open Transcript. It's not formatted but it's all time encoded but you can hide the time codes for copying and pasting. The start of the transcript (not Cerny) looks like this:

    Transcript

    00:00 hi unfortunately we had to cancel the
    00:03 the talk that we had planned for GDC but
    00:08 we do have some super exciting news
    00:10 about ps5 and who better to bring that
    00:15 to you than the one and only mark Cerny
    00:17 without further ado over to you mark
    00:18 thank you Jim there will be lots of
    00:24 chances later on this year to look at
    00:25 the PlayStation 5 games today I want to
    00:28 talk a bit about our goals for the
    00:30 PlayStation 5 hardware and how they
    00:32 influenced the development of the​

    Useful feature hidden away in a submenu!
     
  15. Globalisateur

    Globalisateur Globby
    Veteran Regular Subscriber

    Joined:
    Nov 6, 2013
    Messages:
    3,493
    Likes Received:
    2,189
    Location:
    France
    At the same clocks a console can consume up to 2x more power, we can see this on Pro when you compare dashboard or indies games vs max power consumption. Power consumption depends a lot of actual load. And In many cases on PS4 the thing consumes the most when it's not even in actual gameplay: during custcenes (Cerny talked about it actually), in the dashboard while the game runs in the background or in a menu: in both latter cases it's usually because the framerate is uncapped and runs as high as it can.

    What Cerny has done on PS5 is actually smart and is the way forward in console gaming. Like the share button before I wouldn't surprised if Microsoft copy Sony again and do the same in their next console. The whole package is really innovative. But it's going to depend of the cooling, it needs to be as innovative to cool that much heat. We'll see but I think the only way is to cool both sides of the APU.

    Anecdotally when the Navi cards where first benchmarked I saw a video of a guy who used a big fan in order to cool the back side of the GPU board. Thanks to this he could immediately overclock the card by about 150-200 mhz (don't remember the exact values here). Too bad I can't find the video again.
     
  16. Metal_Spirit

    Regular Newcomer

    Joined:
    Jan 3, 2007
    Messages:
    556
    Likes Received:
    341
    That's irrelevant... ALL consoles are affected by chip quality, and ALL consoles are affected by power consumption. So ALL consoles might have problems with clocks or thermals.
    Thats why ALL consoles are set withing a safety margin to account for those variations.

    Sorry for the ALL in caps, but in the context of the conversation I have to make clear that what you mention is not a specific PS5 thing.
     
  17. RobertR1

    RobertR1 Pro
    Legend

    Joined:
    Nov 2, 2005
    Messages:
    5,740
    Likes Received:
    937
    Sony needs to bin for peak boost clocks being advertised. From a binning perspective that doesn’t change anything. The yields will depend on voltage tolerance range for the bin, assuming the chip can hit the peak frequencies in the first place.

    Since they’re throttling based on power draw, the greater the delta in voltage, the greater the performance delta will be between units or they will have to build their base profiles to the lowest performance envelope (highest chip voltage allowed) to ensure consistency in performance across unit.
     
  18. Xbat

    Veteran Newcomer

    Joined:
    Jan 31, 2013
    Messages:
    1,439
    Likes Received:
    1,025
    Location:
    A farm in the middle of nowhere
    Yup sounds like a no brainier but and it's a big but is the proof is in the pudding and we will see through the life of the PS5 if it's a sound decision or if there might be hidden issues that they didn't predict.
     
    goonergaz likes this.
  19. Metal_Spirit

    Regular Newcomer

    Joined:
    Jan 3, 2007
    Messages:
    556
    Likes Received:
    341
    Trying to explain this and keeping it simple:

    First you need to understand this:

    Imagine your water supply pipeline.
    Did you knew that if all the persons on your street, opened all fawcets at the same time, there would be no water coming out?
    Why? Because pipes are not calculated by multiplying the number of fawcets by the desired water comming out of each.
    There is a zero possibility of every person opening all fawcets at the same time.
    So estimated consumption is made by average person consumption, making an estimation on regulation plans and soil occupation. And even then, only a percentage of that is used, because not all persons will use the watter at the same exact moment.

    The same is made with power usage. Consoles could estimate power for a full 100% usage of all components, lock the speeds, and then make the cooling system.
    You would end with a huge case, and a high cost cooling solution.
    And for what? For nothing! That scenario will never happen. No game will ever use the GPU that way.

    So, workloads are estimated using an average. They check what games are doing and using statistic methods make a determination on what power usage will happen, creating a cooling system for that.

    This will happen on all consoles, PS5 or XsX.

    Note that thermals are caused by power usage, and power usage comes as a result of workloads. And workloads also depend on clock frequency since the system will be making more calculation every second.

    So a better way to try and keep power usage within control is to control also some variables. The most used one is the clock speed. You lock it, so that workloads can be more constant. Your output will no longer be dependable of clock speeds, but only on GPU components usage.

    Even so, GPU clocks are locked bellow the maximum possible. And why? Because of thermal problems!

    Since GPU components are not locked, an increase on their usage above the one expected when creating the cooling solution will increase power usage, so if the GPU usage goes above the estimated power usage, it will overheat.

    But overheating cannot be deterministic. I mean your system cannot simply lock because the system went above the expected heat. So the chip has to have a margin. It can heat above the expected, and that's why fans are prepared do speed up.
    Problem is, the cooling system is not efficient in that way. They were not optimized for those temperatures. And as such, if thermals keep above the ideal, the system will eventually overheat out of control, crash or reboot. Chips have then a safety precaution, where they will turn off if a certain temperature is achieved.

    PS5 goes the other way around.

    First the PS5 will not lock the speed variable or the workload variable. It will be deterministic and just lock the maximum power usage, also locking maximum temperature, and making a coolling system optimized for that temperature.
    This is way more efficient on getting thermals under control.

    This means PS5 is designed to never go above that temperature. But if by any chance, if thermals were badly calculated and temperatures do go up, even then it will not overheat. It will downclock a bit, reducing power usage and keeping thermals in place.

    This means the Chip doesn´t need safety margins to handle increasing in temperatures, and as such you can squeeze the maximum speed out of it, that keeps it within your cooling system temperature control range.

    Hope I made it clear.
     
    #1319 Metal_Spirit, Mar 29, 2020
    Last edited: Apr 1, 2020
  20. Kaotik

    Kaotik Drunk Member
    Legend

    Joined:
    Apr 16, 2003
    Messages:
    9,125
    Likes Received:
    3,014
    Location:
    Finland
    Of course it is not just a specific PS5 thing, but it's different for PS5 compared to XSX because the latter has locked clocks.
    For XSX you just need your chips to reach set clocks, they're locked there and total consumption will vary between consoles.
    PS5 instead uses variable clocks and according to Cerny it's power determined, so each individual console needs to be calibrated relative to it's specific power consumption instead of absolute power or each console would clock different on different loads
     
    blakjedi and PSman1700 like this.
Loading...

Share This Page

  • About Us

    Beyond3D has been around for over a decade and prides itself on being the best place on the web for in-depth, technically-driven discussion and analysis of 3D graphics hardware. If you love pixels and transistors, you've come to the right place!

    Beyond3D is proudly published by GPU Tools Ltd.
Loading...