How does the PS4 differ from a high-end gaming PC?

Sony described its upcoming PlayStation 4 as a "supercharged" PC. However, while it may use many parts found in high-end gaming PCs, PS4 system architect Mark Cerny argues that PS4 has many unique features that separate it from today's PCs.

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Sony described its upcoming PlayStation 4 as a "supercharged" PC. Powered by familiar x86 architecture manufactured by AMD, PS4 is more like a gaming PC than any previous Sony console. However, while it may use many parts found in high-end gaming PCs, PS4 system architect Mark Cerny argues that PS4 has many unique features that separate it from today's PCs.

"The 'supercharged' part, a lot of that comes from the use of the single unified pool of high-speed memory," Cerny said, pointing to the 8GB of GDDR5 RAM that's fully addressable by both the CPU and GPU. "If [a PC] had 8 gigabytes of memory on it, the CPU or GPU could only share about 1 percent of that memory on any given frame. That's simply a limit imposed by the speed of the PCIe. So, yes, there is substantial benefit to having a unified architecture on PS4, and it's a very straightforward benefit that you get even on your first day of coding with the system."

According to Cerny, PS4 addresses the hiccups that can come from the communication between CPU, GPU, and RAM in a traditional PC. "A typical PC GPU has two buses," Cerny told Gamasutra in a very detailed technical write-up. "There's a bus the GPU uses to access VRAM, and there is a second bus that goes over the PCI Express that the GPU uses to access system memory. But whichever bus is used, the internal caches of the GPU become a significant barrier to CPU/GPU communication--any time the GPU wants to read information the CPU wrote, or the GPU wants to write information so that the CPU can see it, time-consuming flushes of the GPU internal caches are required."

PS4 addresses these concerns by adding another bus to the GPU "that allows it to read directly from system memory or write directly to system memory, bypassing its own L1 and L2 caches." The end result is that it removes synchronization issues between the CPU and GPU. "We can pass almost 20 gigabytes a second down that bus," Cerny said, pointing out that it's "larger than the PCIe on most PCs!"

"The original AMD GCN architecture allowed for one source of graphics commands, and two sources of compute commands. For PS4, we've worked with AMD to increase the limit to 64 sources of compute commands," Cerny said. According to Cerny, the reason for the increase is that middleware will have a need to use compute as well. "Middleware requests for work on the GPU will need to be properly blended with game requests, and then finally properly prioritized relative to the graphics on a moment-by-moment basis."

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  • reply
    April 24, 2013 12:45 PM

    Andrew Yoon posted a new article, How does the PS4 differ from a high-end gaming PC?.

    Sony described its upcoming PlayStation 4 as a "supercharged" PC. However, while it may use many parts found in high-end gaming PCs, PS4 system architect Mark Cerny argues that PS4 has many unique features that separate it from today's PCs.

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      April 24, 2013 1:17 PM

      for one a cpu right now wont benefit verry much if any from ddr5, second must gpus barely saturate pcie 2.0(bandwith 16 GBs(almost 20GBs)) and if your talking about a current gen gaming pc its more then likely has pcie 3.0(bandwith 32GBs). most pc gpus have dedicated ram,unless you are talking about a apu, if your using a apu its not a real gaming pc sorry. sony better price this right or pc gamings going to make one hell of a come back.

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        April 24, 2013 1:51 PM

        Wow, the number of levels upon which you have managed to cite all sorts of stats and completely miss the point of all of them is... impressive.

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          April 24, 2013 2:16 PM

          point being is their so no bottle neck anywhere on a pc that impacts performance of current gen hardware

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            April 24, 2013 2:39 PM

            Except that there is, you can't use the GPU on system memory or the CPU on GPU memory without a whole lot of slow copying over PCI-E and coherency issues.

            Integrating everything into one die that has a shared memory subsystem means you can do a lot of very very cool things.

            GPUs don't saturate PCI-E because the engineers that design them do everything in their power to use it as little as possible, because PCI-E is, on the scale of a GPUs bandwidth.. really slow and high latency.

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              April 24, 2013 5:49 PM

              I love every one of your posts.

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              April 24, 2013 5:51 PM

              Boom, head shot.

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              April 24, 2013 5:56 PM

              Toraz droppin' truth bombs.

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                April 24, 2013 9:32 PM

                They're longbow corrosive leech MIRV grenades. Level 61 biatch

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              April 24, 2013 5:56 PM

              butbutbutbut pc master race

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                April 24, 2013 6:13 PM

                The PC master race idiots have been such douchebags the past 3 years I am embarrassed to think I ever used to think that way. I used to belittle console gamers and now I think the people who refuse to play anything but PC games are just closed minded.

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                  April 24, 2013 6:16 PM

                  Pretty much. I definitely prefer my PC to any of the consoles I own but the idea that everything needs to be mutually exclusive is just asinine.

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                    April 24, 2013 6:18 PM

                    The goons miss out on stuff like Bayonetta, God of War, Uncharted, Forza etc, it's madness - plus they have to wait up to a year for games like GTA which are better on a couch with a big TV anyhow.

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                      April 24, 2013 6:35 PM

                      i cant use my pc on my tv? oh wait can look at that.

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                        April 24, 2013 6:39 PM

                        Sure you can - but the vast majority don't or can't easily. Exception to the rule.

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                          April 24, 2013 7:06 PM

                          Such an exception that Steam made it a feature?

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                            April 24, 2013 7:13 PM

                            Yeah a feature that only went into all builds, what? 4 months ago? Which a huge quantity of games don't support, where dialog boxes still come up on the TV just for you to click ok?

                            Sorry, you're not going to sell me - it's not ready for primetime. Not yet.

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                              April 24, 2013 7:30 PM

                              I've started using it specifically to play console ports on my TV from my PC as they tend to be made for controller based play anyways. In those cases it has been a nearly flawless experience.

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                              April 24, 2013 7:33 PM

                              You said exclusive PC gamers are close minded because a) there are console exclusive games we don't get to play and b) some games are better played on the TV. Except you can be a PC exclusive gamer and play everything on the TV easily. So your second point is bullshit, abrasion.

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                                April 24, 2013 7:40 PM

                                Except...for the console-exclusive games. Which is the whole point of why intentionally being exclusive to pc is stupid.

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                                  April 24, 2013 7:41 PM

                                  ^^^^^^^^^^^^^

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                                    April 24, 2013 7:41 PM

                                    (in other words, own both)

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                                      April 24, 2013 7:50 PM

                                      My father had a good piece of advice about women, and suppose it applies here too: Be like Jesus, and love them all.

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                                      April 24, 2013 9:10 PM

                                      I have a PS3 and a PC. I only bought three games on the PS3 in five years. Journey, Battlefield 1943, and MLB 11: The Show. Two of those purchases I regret.

                                      I'm not really interested in any of the console exclusive titles being released. I would buy The Last Guardian, but who knows if that will ever come out. I'm certainly not going to spend $400 on a PS4 just for that game. I would get Forza if I had an Xbox.

                                      I really don't think I'm missing out on all that much.

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                                        April 24, 2013 9:13 PM

                                        How you can not buy Uncharted I do not know, you're not even trying.

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                                          April 24, 2013 9:32 PM

                                          I'm not interested in highly scripted theme park rides.

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                                            April 24, 2013 9:39 PM

                                            #Owned

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                                            April 24, 2013 9:41 PM

                                            The second one was worth a rental. I played them all and wouldn't suggest anyone buy them (especially for $60), but there some good Indiana Jonesy action in there. They're all more entertaining than Indy 4 as far as the story goes, anyway. Just too much terrible shooting, and the climbing and traversal feels like a long QTE that's impossible to fail.

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                                            April 30, 2013 10:07 PM

                                            An extremely fair point here.

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                                          April 24, 2013 9:38 PM

                                          tomb raider is on pc, and imo its better.

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                                        April 24, 2013 10:18 PM

                                        If you have a PS3 and you haven't played Valkyria Chronicles, you've fucked up.

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                                        April 25, 2013 12:27 AM

                                        You never tried out Red Dead Redemption? Wow man, what was the point in owning a PS3 if you only played a few games on it? Waste of money imo.. Demon's Souls was also a great PS3 game.

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                                          April 25, 2013 9:15 AM

                                          Red Dead Redemption and Demon's Souls are both games I want to play. I'll probably pick up Demon's Souls this summer, but I need to beat Dark Souls on the PC first.

                                          I've gotten tons of value from my PS3. It's an excellent Blu-Ray player.

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                                          April 25, 2013 3:29 PM

                                          yeah RDR is one of hte few games I got on the PS3, though my PS3 is F'd up now.

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                                  April 30, 2013 10:06 PM

                                  There's nothing stupid about wanting to play on whatever you system you prefer, exclusively. It's personal choice.

                                  I choose to own both a PS3 and a PC and that works very well for my tastes and interests - though I still find that the PC offers way more benefits to me, gaming-wise, than the PS3 but again, personal preference is what it's all about.

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                                    May 1, 2013 9:13 AM

                                    That's not what I said though, is it? My point is that it's stupid to intentionally exclude yourself from good games just because you have some ridiculous notion that the platform they're on is somehow inferior.

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                                      May 7, 2013 1:57 AM

                                      Your comment here presupposes that they're not going from facts that matter to them vs. their opinion just being a quaint "notion." If a particular factual aspect of a product isn't pleasant or welcomed by that particular gamer, then I see nothing illogical or unusual (at all) about them avoiding a particular platform. Sure, they'll likely miss out on some games but if they had to play those games at the cost of dealing with something annoying or even hated about the platform that supposedly great game is being played on, it may simply not feel worth it to that player.

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                                        May 7, 2013 11:02 AM

                                        We're talking about people who refuse to play any game on a console merely because it's on a console. Not even a specific console but any console. These are not people making rational decisions. Furthermore the idea that dealing with "annoying" things on consoles is so overwhelming that it justifies this attitude is so incredibly laughable that the value of your opinion to me on this subject has plummeted below worthless.

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                        April 24, 2013 7:39 PM

                        Regardless of that rather minor point, intentionally excluding yourself from console games simply because they're console games is beyond retarded.

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                  April 24, 2013 6:20 PM

                  I don't think it's mutually exclusive. I still would rather any competetive FPS be on PC but I own all the consoles and enjoy most of them. Even the Wii U!

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                  April 24, 2013 6:39 PM

                  you know its gone bad when its accepted wisdom at reddit. One of the top comments in a games thread the other day said that consoles allowing for more power via fixed, directly addressable hardware had been "thoroughly debunked" and you could compare consoles to PC specs 1:1.

                  I suspect the reason is most of the posters are barely old enough to remember the last console launch.

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                    April 24, 2013 6:45 PM

                    Even more reason to not read that idiot cesspool of ADD ATTN whore wankery.
                    I now remember 4 console generations :( although I don't recall a lot of the PS1 launch as I was in my "consoles are for babies lol" stage.

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              April 24, 2013 6:35 PM

              I'm still an amateur at realtime stuff, but afaik this is why we still have so much static level geometry despite physics being available - writing updates like kicking a keyboard off a desk just isnt worth the time to write from CPU to GPU memory when you can just say to the GPU "fuckit, use the same data from last frame" and its hundreds to thousands of times faster.

              Its actually crazy how fast you can run into limits trying to update stuff between CPU and GPU, it makes it feel like its 2003 again.

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              April 24, 2013 6:42 PM

              its verry low latency considering on most cpus the pci e controller is built on the die so do some home work before you try to look smart

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                April 24, 2013 7:13 PM

                ?? I am so uninformed, but even I know having the pci-e controller on the CPU die doesn't help it talk to the GPU any faster.
                You are going to get destroyed man if you keep this up. Fanbois don't do well in this place.....

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                April 24, 2013 7:48 PM

                Are you just determined to discredit yourself entirely?

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                April 24, 2013 9:08 PM

                Low latency compared to an outboard PCI-E controller that's accessed over a frontside bus... sure, there's a hop skipped from the process.

                Compared to directly addressing ram from either the CPU or GPU, pulling the data needed to cache, throwing it back to ram it's VERY high latency.

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                  April 24, 2013 9:18 PM

                  addendum: and being able to have the cpu or gpu work on it whilst it's in the cache without thrashing it around is a massive bonus as well.


                  I'm all for absurdly powerful PC's TheBlackThunder, I'm sat at a 4.6Ghz i7 with 16GB of ram and (when it's back from an RMA) a Radeon 7970... But that's a brute force approach, and there are still things that the PS4 platform is going to be able to do faster because it's just a more efficient layout, the PC will pull ahead in some places (and some of them will be important places, make no mistake) but well optimised game vs well optimised game, it's going to run a lot better on the PS4 than on a PC that on paper has equivalent GPU and, well, more CPU grunt, because it's just going to be MUCH more efficient.

                  And that's before getting to things that CAN'T be done in a realtime timeframe on the PC at all because you'd have to shunt data to/from system/video memory over PCI-Express... It's bad enough when there's surplus texture data in a game (off the top of my head the easiest way to see this without having underperforming hardware is Skyrim with HD texture mods) that only needs to be transferred one way. stuttering is not a sign of an efficient piece of hardware.

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                April 24, 2013 9:12 PM

                stop posting

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                April 24, 2013 9:15 PM

                i agree with you and TC is dead wrong. please continue posting.

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                April 24, 2013 9:21 PM

                i've worked on / designed pci controllers...you have no idea what you're talking about

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      April 24, 2013 1:33 PM

      If I could swap out parts of that 'supercharged PC' and mod my games I'd be well onboard.

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      April 24, 2013 1:36 PM

      Nice try Sony

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      April 24, 2013 1:45 PM

      I'm not sure how you can supercharge a PC. It doesn't have an intake manifold OR a camshaft. Hell it doesn't have any kind of combustion...

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        April 24, 2013 1:57 PM

        Tell that to Microsoft. They might know a thing about their console and combustion. :P

        I'm on my 3rd xbox and I haven't had a problem since.

        /knockonwood

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        April 24, 2013 3:30 PM

        I saw a banner ad telling me how to supercharge my PC, so it's definitely possible.

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      April 24, 2013 1:47 PM

      well we can be sure it can't be hacked, sony has never been hacked ever

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      April 24, 2013 3:19 PM

      I call FUD on what Cerny said about the PC only using 1% of the available memory per frame. He seems to conviently forget that the GPU itself has a large amount of DDR5 memory and has been that way for years. the DDR5 amount on the GPU may not be 8GB but it doesn't need to be. The CPU has enough memory to do the task its needs to do as well. Also the data is loaded to the GPU in batches not necessarily on every frame.

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        April 24, 2013 4:26 PM

        From reading the article, I got the impression that Cerny was talking about taking out the batching/context switching normally required for CPU to GPU communication, essentially allowing large memory transfers within any frame by removing the need for caching on both the GPU and CPU sides.

        It's my understanding (which I admit may be completely wrong) that any given frame, which essentially corresponds to a function call and may be nested, is really only dealing with a very small bit of data at a given time. Since writes to memory essentially require that a chunk of memory is locked, and the locking context switching is expensive, CPUs and GPUs alike resort to caching, rather than trying to write out to memory at the exit of every frame. This is compounded by the fact that system memory and graphics memory are physically separate in general-purpose computers, so on top of locking and caching, communication is required between processors to transfer any data between them.

        Cerny seems to be stating that the shared GPU/CPU memory and a dedicated non-locking memory access bus between the processors removes the overhead of locking and buffering, which makes sense to me. Basically, the entire bandwidth of the memory pipeline can be utilized constantly for certain operations, and no extra synchronizing needs to be done between processors.

        I think the real benefit of the massive amount of memory is that there is much more room for creating these unbuffered chunks of the memory pipeline. If the operating system can set up a given 2GB chunk of memory only for CPU writes and GPU reads, and viceversa, that's an incredible amount of data that can simply be pushed through at full speed. Or multiple cores can each have their own write chunks, optimized however to take full advantage of the bandwidth. Any core may not need that much memory to do its job, but when you're talking about allowing the processors to write out as fast as physically possible, the worst thing you can do is have your speeds bound how much RAM is available.

        I don't know if what I just wrote makes any sense.

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          April 24, 2013 5:33 PM

          *SNIP* any given frame, which essentially corresponds to a function call *SNIP*

          Actually in modern-day game engines that use an object-oriented programming approach will usually have a FrameUpdate() function/method attached to each object. That function in turn will be called every single frame as long as that object is currently loaded. (objects can be anything, literal objects, cameras, AI routines, etc.)

          Of course it gets more complicated as you generally do not want code run every single frame on many different types of objects. (For example anything that would modify what shaders are applied to an object would be pointless to be called/updated unless it were actually viewable by a player). In which case then a similar function like a OnViewFrameUpdate() method is used instead so that its only called if a raycast from camera is able to hit/view the object depending on the type of camera.

          AI however, you generally want in the standard FrameUpdate() as you wouldn't want the AI to stop and wait for the player to look at them. (Simpler games, you could probably get away with this).

          The trick is you want to cut down on as much code as possible being called every frame, however, generally all game objects and all the sub-objects that make up or are a part of other objects have co-routines to handle things on every frame.

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            April 24, 2013 6:04 PM

            Perhaps I misunderstood the context of "frame." I've been talking about stack frames (see here, https://en.wikipedia.org/wiki/Stack_frame#Structure), basic units of execution for pretty much any program, game or otherwise. If I misunderstood the meaning of "frame," then pretty much everything I wrote doesn't apply.

            That being said, from a general programming standpoint, the PS4 looks pretty hot.

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      April 24, 2013 3:28 PM

      i'd really like to know the internal politics as how the team was formed to design the ps4. am i the only one surprised that it wasn't designed by/in japan?

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        April 24, 2013 4:41 PM

        the ps2 and ps3 were largely US-designed, though to a jap spec. dunno about the ps1

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          April 24, 2013 4:53 PM

          erm, I think

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          April 24, 2013 9:30 PM

          ps1 used a mips CPU, american based company, ps2 used their 'emotion engine' developed by sony+toshiba, ps3's cell was a joint venture between sony, toshiba and IBM but I think you could call that an american design since it's based off the Power PC architecture.

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            April 25, 2013 12:40 AM

            the ps2 GPU was US-designed, I remember reading

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      April 24, 2013 4:00 PM

      I couldn't really care less about pre-release tech talk relating to the PS4. Let's just wait and see how the games look and perform when the console is out.

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        April 25, 2013 7:35 AM

        I agree. They hype up consoles with all this tech talk and then when it releases everyone QQs about how Sony/Microsoft/Nintendo lied.

        You're all falling into their trap.

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      April 24, 2013 4:54 PM

      For the real truth listen to the This American Life episode "Giant Pool of Memory"

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      April 24, 2013 6:46 PM

      this reminds me a lot of how the PS3 was going to be the most ADVANCED CELL PROCESSOR OF EVER!

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      April 24, 2013 7:14 PM

      Can I hook a mouse and keyboard to it?

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        April 25, 2013 1:07 AM

        I wish, but probably wont happen. Would be smart if they did, they'd steal a lot of PC customers.

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          April 25, 2013 1:20 AM

          like the ps3 I bet it'll be allowed but not mandated, so no almost no dev will bother :(

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            April 25, 2013 12:34 PM

            The x86 architecture may actually give you your wish, though.

            Since the impedance mismatch between PS4 and PC will be much lower, it may be a no-brainer for developers to just throw in PC peripheral support during development and just leave it there. Theoretically, the same interface will be available for both platforms (taken advantage of by game engines, rather than individual games themselves,) so they may actually be making more work for themselves by removing support rather than keeping it in place for all versions.

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      April 24, 2013 7:39 PM

      all i know is that i will be able to pay a reasonable price and be able to play every game till the end of its life without having to micromanage performance.

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