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#1 |
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Member
Join Date: Aug 2011
Posts: 501
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I hope this is the right board for this, but since it ties in with consoles I figured why not as it will get moved or closed if it's not. This comes from a discussion with a fellow B3D member elsewhere.
So is it really possible to estimate how much of a PC's hardware is utilized vs a console? This is based in part on a tweet from Carmack that essentially says a PC's hardware is only used at about half of it's power. He makes a comparison based on a PC and console having the same hardware. This is obviously based on things like APIs, inability to focus on one hardware spec, PC OS, and whatever else I'm forgetting to list. First is it really possible to estimate how much a PC's hardware power is utilized for a game? And if so is it really 50%? That sounds like a lot. |
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#2 |
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Senior Member
Join Date: Oct 2004
Location: The Netherlands
Posts: 2,231
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obviously a pc is using 100% of the hardware available as well only some power gets ''wasted'' on the OS, API's etc. So it's a question of which platform is utalizing it's hardware more efficient. That's something a pc just cannot win because it's an open box and besides the OS, API's etc devs also have to keep in mind their games will likely be running on atleast 3 generations of hardware.
As Carmack wrote most of it probably comes from single platform focus. I don't believe pc overhead vs consoles means a pc could do 50% more of whatever it's doing just by using more efficient/streamlined API's etc. Most of it would come from having one single spec.
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I cut an elderly woman off and she spun out and crashed... but its alright... cause I've got a Jaaaaag |
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#3 | ||
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Member
Join Date: Aug 2005
Posts: 323
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We had a thread kinda about this already. Good post in that thread hat goes with carmack quote.
http://forum.beyond3d.com/showthread.php?t=61841 Thread got locked btw Quote:
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#4 |
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Naughty Boy!
Join Date: May 2012
Posts: 200
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Also lack of optimization. Not because of PC not being "a single spec", but in general. I believe it has to do with the market/climate; why should developers work hard; the majority of PC gamers pirate anyway. While the ones who do pay for games, probably also buy some extra GPU's, ram, faster HDD's, ...
Not a single PC game out now, feels like it really makes use of all the extra hardware. To me that is lack of optimization. They just port a console game for a little while and then call it a day, that's how PC development feels to me at the moment. So Carmack is right in a way, but I strongly believe there is also a severe lack of optimization of which Carmack is afraid to speak of.
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"If we look at this objectively, then color is definitely scientifically better." |
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#5 |
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Beyond3d isn't defined yet
Join Date: Jan 2008
Location: New Zealand
Posts: 3,052
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Why optimise towards a continually improving target? If developers want a better game on a console they have to optimise, if they want a better game on the PC they just increase the min requirements.
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#6 |
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Member
Join Date: Aug 2011
Posts: 501
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To help add some persperctive on this by using a rough scenario, how it sounds to me is that if let's both the console and PC have a 1 TFLOP GPU. It would seem that at best using Carmack's tweet, the console's GPU would have a max of say 900 GFLOPs used (it still deals with the same things only much leaner) while the PC GPU is only having 450 GLOPs used. I'm not saying this is the case before anyone believes that. I'm just trying to give an idea of how I'm seeing this to get a better answer.
Side note: I remember seeing that thread, but even saying "kinda" is pushing it IMO. |
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#7 |
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Naughty Boy!
Join Date: May 2012
Posts: 200
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Squilliam, that kind of attitude is the reason why PC is lagging behind when you compare the specs to the things that devs do with it.
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"If we look at this objectively, then color is definitely scientifically better." |
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#8 |
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Junior Member
Join Date: Jan 2012
Posts: 10
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I think 'power' is a poor term, hardware utilisation would be a better term.
No games could possibly hope to achieve 100% utilisation, ever, fact. There will always be occasions when the CPU is waiting on memory, memory is loaded into the cache which isn't used wasting bandwidth, SIMD units are unused, branch predictions goes wrong and we get a roll back etc.. Keeping all CPU pipes 100% utilised in near impossible even for the most optimal hand assembly coded loops, we might get near for some very specifc cases but this is extremely rare in practice. Similarly on the GPU it is impossible to keep texture units, render target bandwidth and all the cores perfectly utilised all the time. On consoles we have a much thinner API so less 'fat' between the game code and the metal and very little or no contention for the CPU/GPU resources. Context switching CPU cores to perform other work is incredibly painful. So without even trying by running on a console your title is getting more out of the machine. Then of course there is optimisation, we can optimise for the consoles because they are fixed specifications, because we get to know what the hardware is doing and because we get good tools to help with performance tuning. The real killer on PC's is having to spend time coding scalability into your title (particularly when this means different data) rather than spending that time optimising. |
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#9 |
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Moderator
Join Date: Feb 2002
Location: Redmond, WA
Posts: 3,201
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On the technical side trying to support a wide variety of hardware is really hard and introduces a lot of overhead, you spend your optimization dollars on your min-spec machine, not the just released mega machine. CPU/GPU balance is all over the board, often lower end machines have "fast" CPU's and terrible GPU's, and even if you were just targeting the high end, it's impossible to answer simple questions like "what is a high end PC".
But to my mind the real reason PC's fall short is money, with a few notable exceptions there just isn't the $ in the PC market to justify a $70M spend on an a title aimed at high end PC's. |
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#10 | ||
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Member
Join Date: Aug 2005
Posts: 323
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Does anyone else think its crazy carmack can even post on twitter?
Anyway some good quotes from carmack about this topic. http://www.pcper.com/reviews/Editori...d-more/Intervi Quote:
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Yeah that thread wasnt just about this but by page 3 it was taking about this topic. That is where I got that quote from. |
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#11 |
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Member
Join Date: Aug 2011
Posts: 501
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Thanks for the responses so far, but the answers are saying what I have a decent understanding on already. I have a good enough grasp on the "why". I'm trying to find out is it possible to estimate how poorly utilized PC hardware is vs a console. Because when I see Carmack's comment I'm pretty much left to believe that in a perfect scenario a PC using a 7970 with no bottlenecks to the GPU and the PS4 with it's target GPU and no bottlenecks is almost on par with the aforementioned PC because of how underutilized the PC's hardware would be.
For those wondering this is the person I had the discussion with. Still you can't look at it as the GPU surpassing it's theoretical target. That's not logical. It's just better utilized. |
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#12 |
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B3D Scallywag
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It's worth noting that when Carmack says 2x he's talking about DX9. DX11 will reduce that somewhat.
Also, that level of optimisation will only apply to games at least a couple of years into the console lifescycle because of the time it takes developers to optimise console hardware. So I wouldn't expect a 1.8 TFLOP GPU in PS4 to be matching the 7890 on day 1. Two years down the line in newer games it might but of course by then the 7970 will be mainstream level performance. Finally, when we say PC's have half the efficiency of consoles that would only be at the console level graphics. i.e. it would take double RSX performance to achieve PS3 level visuals in a modern game. Once you start scaling the graphics up I expect PC games get far less efficient than that due to the lack of optimisation given over to graphics beyond the console level.
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#13 |
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Moderator
Join Date: Feb 2002
Location: Redmond, WA
Posts: 3,201
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No it's not possible, because it's not utilization of resources the way your thinking about it.
Carmack is talking about a very specific usecase, updating textures, in that one case there is an enormous overhead resulting in a speed penalty of several orders of magnitude, this is especially true if you intend to update only a portion of the texture. The same is true to a lesser extent of most GPU level resources (index buffers/vertex buffers etc.). In the more general case, it's not that simple, just because you're running on a PC your pixel or vertex shaders don't magically run at 1/2 speed. The only thing that the API/driver overhead can do to hurt performance is to starve the GPU, if you are dynamically updating GPU resources this can certainly happen because of fences inserted by the driver in order to respect locks. In practice however if you understand the restrictions the environment places on you, you can get similar utilization to consoles for the general submit triangles and render them use cases. you have to limit my batch counts and you have to be careful with resource locking, but unless you are trying to do something overly clever % utilization can be similar. What you can't do it tailor your art/design to a known quantity and that is a huge disadvantage, but you can't quantify it in flops, or as a percentage. FWIW the last time I sat through an MS conference some 360 games did still ptimize shaders by hand which will buy you something, and it's something you wouldn't see on a PC, but outside of pathological cases where the compiler generates stupid code, it's not going to be a huge saving. |
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#14 | ||||
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Member
Join Date: Aug 2005
Posts: 323
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First off the whole debate was the "PS4/nextbox would not be able to handle square enix demo, UE4 demo and starwars 1313 because those games were running on "high end pc." If even if they do they will never look like that because these games were running on a 680 series card which the console could not match." Which i said was untrue because the given specs of the ps4 would be able to handle any PC game running on a 680 gtx and look about the same at console resolutions. I give many reasons why and look they been repeated many times in this thread.... So they real question was, given the PS4 specs could it match a 680 GTX running a game? Last edited by Kb-Smoker; 09-Jul-2012 at 23:00. |
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#15 | ||
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Member
Join Date: Aug 2011
Posts: 501
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Quote:
http://www.neogaf.com/forum/showpost...postcount=5967 Quote:
And with the last sentence I didn't feel like there was a dramatic benefit so you're confirming what I felt, but wasn't sure about due to no personal experience. I didn't say you did. I'm saying you can't look at it from that perspective like when you said the GPU in my scenario was "2 TFLOPs" in your view. Last edited by bgassassin; 09-Jul-2012 at 22:21. |
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#16 | |
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Member
Join Date: Aug 2005
Posts: 323
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The console gains performance, the pc doenst some how lose power. For you example you have 1 tflop pc gpu and 1 tflop ps4. The ps4 would get around double the performance running a game built for it compared to a pc game. The pc cannot lose performance. Like he said the pc hardware doesnt start running at 50% Think of it this way. You have 2 stock mustangs, now you take one and dyno tune it. You still have the same engine but this improves the performance. The stock mustang doent lose performance. Now consoles take this one step farther, they design the system just to run games. Using the mustang again you remove the seats, radio, a/c and improve performance by reducing weight. There is no debate there is performance improvements in consoles. The only debate is how much but even then there is no one answer. Not sure why you are so focus on this when I was talking about the next gen demos running at E3. I was using john carmack as an example of how it was possible, not saying it some golden rule. Last edited by Kb-Smoker; 09-Jul-2012 at 23:36. |
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#17 | |
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Senior Member
Join Date: Feb 2002
Location: San Francisco, CA
Posts: 1,571
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I quite dislike your mustang analogy. Why bother ripping out the AC, seats, and other weight adders like power windows when you can keep all this shit in there and still go faster with a little investment? I'd much rather pull up in a fast and functional mustang then one that has taken comfort and shoved it out the window. Pointless to me to tune a stock Mustang when I could spend an extra couple hundred bucks at performance upgrades and get the tune for free. That and the fact is that the PS4 might be the mustang, then that would make the PC a freaking tank that is pure brute force and is faster than a mustang. So the mustang might be more efficient, but the tank makes up for it in brute power and ends up faster in any case. It's not a stock mustang vs. a tuned mustang argument...it's a stock tuned mustang vs. a loaded tank with speed. Of course most PC's aren't like that, and will be like matchbox cars compared to mustang at PS4 launch. Still, why do an apples to apples comparison when we can do a apples to oranges comparison? |
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#18 | |
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Member
Join Date: Aug 2005
Posts: 323
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Again this was really about PS4 running the next gen demo at E3, it got twisted into this debate. |
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#19 | ||
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Member
Join Date: Aug 2011
Posts: 501
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#20 | |
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AndyTX
Join Date: May 2004
Location: British Columbia, Canada
Posts: 1,846
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The whole topic is a bit silly TBH - outside of very specific cases like Carmack mentioning updating textures (where there's an abstraction penalty precisely because guess what, there's actually implementation differences!) you can't draw any general conclusions. Furthermore since almost no one bothers to optimize for PC (since frankly it's just a lot faster in the places that you'd typically optimize, even the day the new consoles come out), it's hard to compare the "speed of light" in both cases. I've actually gotten a bit cynical about this entire argument lately since there's so many unsubstantiated comments flying around one way or another that are just outdated or untrue. Hell a lot of people on my twitter feed are just discovering DX11 (presumably finally moving to new console development) so I'm gonna go ahead and claim that the vast majority of game developers are not really even qualified to make a comment on this... again, excepting very specific use cases like Carmack's, but even he admitted to not having tried an API that has been out for years now. There was talk of some of this a few months back and claims of how many draw calls or state changes could be done in one place or another, most of which turned out to be nonsense when Humus and I and a few others put them to the test on PC. Thus you can understand my cynicism to this entire discussion. Let's just get to the heart of this - what exactly are you trying to do/figure out here? Because the question is ill-formed, and it makes it sound like you have some sort of agenda that you're just trying to justify with cherry-picked "facts". If that's not true, great, but please enlighten me to the end goal here.
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The content of this message is my personal opinion only. Last edited by Andrew Lauritzen; 10-Jul-2012 at 02:51. |
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#21 | ||
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Member
Join Date: Aug 2005
Posts: 323
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The funny thing about a prius when racing it you get terrible mpg. Like on top gear they got around 12 or something silly... |
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#22 | |
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AndyTX
Join Date: May 2004
Location: British Columbia, Canada
Posts: 1,846
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The content of this message is my personal opinion only. |
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#23 | |
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Member
Join Date: Aug 2005
Posts: 323
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![]() The whole debate started over this statement, can the ps4 at the leak spec handle the games running on single 680 gtx: UE4, starwars 1313, and square enix demo all at e3 and look about the same at console resolution. edit: to be fair to carmack they do not use dx they use opengl. That is why he does not work with it... Last edited by Kb-Smoker; 10-Jul-2012 at 03:03. |
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#24 | ||
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AndyTX
Join Date: May 2004
Location: British Columbia, Canada
Posts: 1,846
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Upon rereading your original question, I guess I'd answer it like this:
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That said, I'd still say I think low level APIs are interesting, and you do lose *something* to the API. Specifically on integrated graphics, as Carmack mentions, the current APIs are not particularly well suited. But that's sort of a separate topic honestly.
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The content of this message is my personal opinion only. |
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#25 | |||||
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Member
Join Date: Aug 2011
Posts: 501
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