PS4: Sony Earlier Thought About Slow GDDR5 + eDRAM (1088GB/s)

Mark Cerny reveals the design process behind the PS4.

[iGAM3R-VIII]

well it would have been harder to code if they chose the slow GDDR5. Good move Cerny

[Cueil]

I know you're excited, but slower ram doesn't make it harder to code for and eDRAM is something developers already use in the X360 so it's not something they don't have a firm grasp on

[sibbor]

He's probably referring to the eDRAM that they would've included. That would've made it harder to develop for. Also the game developers requested a unified memory pool from Sony, unlike what can be found in current-gen and Xbox One for that matter. The game developers has spoken!

"For example, if we use eDRAM (on-chip DRAM) for the main memory in addition to the external memory, the memory bandwidth will be several terabytes per second. It will be a big advance in terms of performance."

"However, in that case, we will make developers solve a puzzle, 'To realize the fastest operation, what data should be stored in which of the memories, the low-capacity eDRAM or the high-capacity external memory?'"

"We wanted to avoid such a situation. We put the highest priority on allowing developers to spend their time creating values for their games."

Source for this old quotes:
http://techon.nikkeibp.co.j...

[iGAM3R-VIII]

"That sounds great doesn’t it? But Cerny said that it would have been difficult to code for it in a straightforward way and developers had to come up with a separate technique to take full advantage of it."

"unified memory at a 176GB/s would have made it really easy for developers to code for and it was their philosophy to provide a simple architecture with the PS4."

My proof. It is harder to code, so I did not pull it out of my ***. Thank you @sibbor to clearify to these people about my comment

[humbleopinion]

The article actually confuses Slow/Fast versus Wide/Narrow.

256-bit GDDR5 is not "faster" than 128-bit GDDR5 just like a 4 lane highway is not "faster" than 2 lane highway. It has a higher bandwidth which means you can push through more sfuff at the same time, but it's actually latency which measures to how fast the memory really is (how much time it takes for a single transfer to get from point a to point b).

[dantesparda]

You're right the GDDR5 would still have ran at 5.5GHz, its just the bandwidth would have been cut in half by the bus (256bit vs 128bit).

Also X1 fanboys need to realize that the X1 only has 102gb of bandwidth to 32MB! thats it! to it 8GB's of DDR3 RAM (which runs at 2.13GHz/256bit) it only has 68GBs of bandwidth, that is a huge disadavanyage to the PS4!

[Cueil]

@dantesparda that 32MB is on die and Microsoft also has hardware compression/decompression on the Move Engines... and 8gigs of ram is still 8 gigs of ram... MS could let developers use page file system and that would be a big help

[nveenio]

If you have two funnels, one with a one-inch spout and one with a three-inch spout, which would funnel a gallon of water faster?

Right. When it comes to volume, wider = faster. Not faster per water molecule, but faster for the gallon.

[humbleopinion]

@inveni0

Wider is not faster. If one funnel allows water to go through in a shorter time then the first drop of water will get out faster. That's latency.

Higher bandwidth means that even if the latency is slower, the overall throughput can be higher because multiple drops of water can pass through simultaneously.

So it all comes down to what you require: higher throughput (particle simulation, graphics rendering) or higher speed (AI, sequential calculation etc)

[TrevorPhillips]

Smart move Mark! PS4 is a beast anyways and cannot wait for it to be released :)

[weirdo]

sexy. i just can't imagine a console with anything less than gddr5 memory, can you? (giggles)

[Fishy Fingers]

Yeah, you've probably defended one for the last 8 years.

[CRAIG667]

haha!

[Minato-Namikaze]

Was GDDR5 available 9-10 years ago?

[wishingW3L]

the first production of GDDR5 were available in 2008 and only in 512MB modules you know. All last gen consoles used GDDR3 because that was the best in its time.

[windblowsagain]

lol.

But the PS3 did have the XDR Memory running @ 3.2ghz.

[B-radical]

1 SRAM is static while DRAM is dynamic
2. SRAM is faster compared to DRAM
3. SRAM consumes less power than DRAM
4. SRAM uses more transistors per bit of memory compared to DRAM
5. SRAM is more expensive than DRAM
6. Cheaper DRAM is used in main memory while SRAM is commonly used in cache memory

[tarbis]

In other words Mark is preventing another PS3-esque hard to develop hardware. Good move on their part. Satisfying both developers and consumers at the same time.

[Cueil]

No... it's the same idea behind the xbox 360's design... so it would have NOT been hard to program for...

[mmj]

The fact is though Sony considered Microsoft's method but opted against it because they felt it it would be more difficult for developers.

With PS4 developers can just store everything conveniently in memory, with Xbone they are going to have to still juggle data.

[Cueil]

a 12 oz bottle of coke is a 12 oz bottle of coke no matter how big the lid is

[Foxgod]

Slower gddr5 + edram would have given them better timings tho.

physics and AI are not friendly for Gddr5, due to timing problems with Gddr5 memory (the time to read and access the next file after loading the previous one is longer then with Ddr3)

The ps4 will have an advantage at games that barely contain physics and AI, because at games like that the XB1 would not be able to keep up with the Ps4 its ability to process bigger data at a higher speed.

However, most games these days contain a lot of physics and ai, and the better timings in Ddr3, combined with the ESram for bigger output, may give the Xb1 a surprisingly good performance at general games, much better then people expect right now.

[DoesUs]

No.

[Foxgod]

Good argument, but the fact that they thought about going for a slower form of Gddr5, means theres a downside with the speedier one, the simply went with the faster one as thats easier to market.

You should read up on Gddr5, its actually the same kind of memory as DDr3, with one important difference, they upped the bandwith, which sacrifices the good timings that DDr3 has.

Ms went with ESram, to make up for the lack of Gpu ram.
But sony only has GPU ram, and no regular ram, so it lacks the good timings that general ram offers, i am curious to see how it will play out.

[kneon]

Foxgod you make no sense whatsoever. You obviously don't know what you're talking about, you just read some stuff on the internet that you don't understand and regurgitate it here.

GDDR5 can have higher latency that DDR3. But it's actually not the GDDR5 that causes the latency, it's the memory controllers. And even so this latency is measured in nano-seconds.

But latency would only matter for a single threaded application that has to access memory and wait before it can do anything else. For an application with many data intensive tasks to do it doesn't matter, the bandwidth is what matters and that is why GDDR is used with the GPU. Games have many data intensive tasks going on at once so bandwidth is critical.

There is a reason GDDR is used with GPUs, it's because it is the best solution to the problem currently available

[JokesOnYou]

Kneon I dont think Foxgod is too far off even you are not really contradicting him I mean you admit GDDR5 brings with it higher latency whether its the controllers or not the point is DDR3 is lower and nano seconds are huge when your talking about hardware performance:

"The PS4 has 8GB of GDDR5 RAM, providing 176GB/s of bandwidth to both the CPU and GPU. The Xbox One mostly ameliorates this difference with 32MB of high-speed SRAM on the GPU, but it will be a more complex architecture to take advantage of."
http://www.extremetech.com/...

"To make up for the gap, Microsoft added embedded SRAM on die (not eDRAM, less area efficient but lower latency and doesn't need refreshing)."

"There are merits to both approaches. Sony has the most present-day-GPU-centric approach to its memory subsystem: give the GPU a wide and fast GDDR5 interface and call it a day. It’s well understood and simple to manage. The downsides? High speed GDDR5 isn’t the most power efficient, and Sony is now married to a more costly memory technology for the life of the PlayStation 4.Microsoft’s approach leaves some questions about implementation, and is potentially more complex to deal with depending on that implementation. Microsoft specifically called out its 8GB of memory as being “power friendly”, a nod to the lower power operation of DDR3-2133 compared to 5.5GHz GDDR5 used in the PS4."

"Even if Microsoft can’t deliver the same effective memory bandwidth as Sony, it also has fewer GPU execution resources - it’s entirely possible that the Xbox One’s memory bandwidth demands will be inherently lower to begin with."
http://www.anandtech.com/sh...

-This is from neutral site that do tech analysis for a living the general consesus seems to be even without X1 eSRAM that DDR3 is just slightly underpowered compared to DDR5 due to trade offs in latency however with eSRAM their basicly on par or a negligible difference with the caveat being that the eSRAM makes X1 a bit more difficult for devs but obviously nothing like the cell, in fact they have experienced this already with the 360's eDRAM.

[Salooh]

In a short way .

DDR3 would be better for the multi tasking stuff and apps because it send small data faster . While GDDR5 is better for games because it send a big amount of data faster.

Consoles for games so GDDR5 is what it needs.

[imt558]

@kneon & Jokes :

Well, PS4 has no any bottleneck because "Onion" bus. So, no GDDR5 latency and any bottleneck :

http://www.neogaf.com/forum...

[Foliage]

Joke and Fox; that was completely pathetic. Finding google is a great step; but you understand absolutely nothing about what you posted. It's incredibly obvious to just about anyone with an ounce of hardware knowledge.

Your comments make no logical sense at all.

The eSRAM is COMPENSATION for going with the slower DDR3 RAM. It's not enough to make a huge difference; 32mb is horribly small when we're talking about HD quality graphics and computations. It doesn't matter that it's almost as as GDDR5; there just isn't enough bandwidth.

Strike 1, Xbone

The XBone has 5 GB of RAM for games; versus the 7 GB for games the PS4 features.

Strike 2, Xbone

GDDR5 is on a completely different level than the dated DDR3 technology. The latency issues you think you discovered from your google search are insignificant. You just don't understand how RAM works.

Strike 3, Xbone

PS4 has ultra fast RAM and can access all of it when it wants. Xbone has slow RAM that it can access and a minor amount of RAM that can only be utilized in 32mb that's "MB" usages.

Are you shitting me?

Kill shot, you're dead Xbone.

[Ritsujun]

JOY's joking on herself.

[Drekken]

Sony should have hired you to created the PS4. I am sure that is the only way they would have gotten it right. Believe.

[SniperControl]

If there was a fanboy statement, that was it.

[MajorLazer]

@Foxgod

Stop! You are using logic. They don't like that

[XabiDaChosenOne]

An example of Foxgods oversimplified logic: 2 is more than 1 therefore 2 NESs Have more processing power than a PS3! Yay!

[Foxgod]

@Kneon
I could accuse you of the same thing.
You pretty much summed up what i typed, but you used more technical terms, i tried to explain it in a more simple way so that more people could understand it.

And multiple threaded applications also suffer from it, it doesntm atter if you have 1 data stream or 8, if they stumble over a large flow of small data, it would still slow the memory down a lot.

The bandwith is only critical is your constantly pushing large data as i already said.
However, games these days are almost half cpu intensive instructions.

The reason there are no gaming pc's with only GDDR5 is because DDr3 is too important for games, so an ideal setup is one that has both DD3 and Gddr5.
Physics and ai stuff are cpu intensive instructions and are loaded trough the bus to the regular ram, because its a pain to let the gpu do it.

Theres a reason why gddr5 is only used with gpu's, because thats where it benefits, not in the main architecture.

[lsujester]

An ideal setup would be both GDDR5 and DDR3, however, the AMD APU only has one memory controller from what I understand.

I also don't think the comparison to gaming PCs is entirely accurate, because no matter what a PC is used for, it still has to be able to run Windows, and other non-gaming programs. Consoles don't have to (yes, there is an OS, but barely) and apps like Netflix, Hulu, etc are hardly taxing.

While CPU may be a little happier using DDR3, being consoles are mainly used for gaming, I think GDDR5 is still a better option. Especially considering how low-powered these CPUs are. I don't think they're going to be memory limited, no matter which set up you go with.

[Hicken]

It's amazing how people continue to factually prove you wrong, and yet you somehow still press on. I mean, you can be wrong from start to finish, with evidence from every possible source, and rather than admit you're not right, you'd prefer to call EVERYTHING that disproves you fanboyish.

Honestly, I don't know whether to praise your determination, or laugh at your utter stupidity.

[wishingW3L]

if what you say was true then they would have gone with that set-up but they didn't. On top of it, the PS4 was made with Game Developers' feedback which further renders your argument irrelevant since you're not even a real Game Developer to begin with.

Haven't you seen the reaction of Game Developers about the unified memory pool of GDDR5? They are very happy about it. In fact, much more happy with it than with XB1's set-up.

[XabiDaChosenOne]

"The ps4 will have an advantage at games that barely contain physics and AI" lol seriously? And by reading these comments, I see that your propaganda has inspired misplaced hope in your fellow MS enthusiast. Their is not one launch game for the Xbox one that has A.I as advanced as Killzone Shadow fall
http://gamingbolt.com/killz...

[DJMarty]

@Foxgod - No Sony modified the read and write of the GDDR5 to and from CPU/GPU, they can both have direct access to ram cutting out cache's etc, meaning it's faster still.

[dantesparda]

Its obvious Foxgod has no idea what he's talking about and making sh!t up, pathetic! Then why did MS chose 2.13Gz DDR3? instead of the lower latency 1.86GHz? you people are dumb as rocks and are just obvious fanboys. MS went with the higher bandwidth chips, Hmmm, hmm, hmmmm

Also, every new RAM iteration has what? higher bandwidth and higher latency, hmmm, hmmm, hmm, guess they dont know what they are doing either.

[DoesUs]

Mark Cerny is the best thing to happen to Sony in years. The speaks, you listen.

[Supermax]

Foxgod people don't read here,this is n4g.for everything ps3 did wrong at its launch they made up for it in the long run Microsoft will adapt and do the same.

[Foxgod]

I agree.

[Nathaniel_Drake]

Just how MS adapted to Sony and released a console later with HDMI and wifi built in, yeah they are really good at followIng good point /s

[GCO Gamer]

When the Xbox 360 originally released, Wifi only took like 2 things at once.

[saggysack79]

remember the cpu and gpu are on the same die which means the ram is fed directly to them, this can only mean one thing GREATNESS AWAITS

[RiPPn]

Easiest platform to develop on should make it the lead platform to develop on!! Good news for PS4 owners!!

[Belking]

I keep telling you people that sony has no real RAM advantage when it comes to performance. You will never hear Sony say that their RAM is superior to that of MS. They will only speak on it from a developers point of view. All they did was go out and copy what MS did with the xbox360.

[wishingW3L]

because the X360 had x86 architecture and a SoC right? o_0

[Belking]

Come back to earth nemoid...lol I was talking about RAM. They copied the unified RAM design of xbox360.

[Foliage]

You realize that the 360 and Xbox One RAM architecture was largely copied from the PS2, right?

Microsoft have never had an architecture based off the amazingly fast high quality GDDR5. Go back to school, kid.

[Furi17]

Unified pool + unified bus <----------> Exotic esRAM to fix slow bandwidth.

[Mikeyy]

@Belking

What are you talking about? The PS4's memory architecture is nothing like X360s. The XBONE is using the same setup as the X360.

The PS4 is just using strait 256-bit GDDR5. Developers will just dump the data there and be done with it, there will be no juggling eSRAM like they have to do on Microsofts console.

To use the Xboxs RAM, developers will have to take extra steps. We already know from last gen, 3rd party developers do NOT like to take extra steps.

Good luck to you.

[Belking]

PS4 RAM is unified just like xbox360 was. What are you smoking? Last gen ps3 RAM was split. Where you been waldo?

@MysticStrummer below.

PS4 only has superior hardware in your head. In your head the new Killzone and driveclub runs at 60FPS but in reality they do not. That's not a good example of stronger hardware. PS4 will not outperform xb1 just like ps3 didn't do it to xbox360. It's ok to dream though. No harm there.

[clrlite]

I lol'd at "good luck to you".

[Felonycarclub8]

PS4 will not outperform xb1 just like ps3 didn't do it to xbox360. LMFAO sorry but the ps3 outperformed the 360

[MysticStrummer]

"I keep telling you people that sony has no real RAM advantage when it comes to performance."

So you admit you lie a lot.

Good to know.

"You will never hear Sony say that their RAM is superior to that of MS. They will only speak on it from a developers point of view."

What other valid point of view is there?

"All they did was go out and copy what MS did with the xbox360."

No. One's memory structure is like 360's. PS4's is not.

PS3 was more complex to code for than 360, and now One is not only more complex to code for than PS4, it also has inferior hardware.

[SpinalRemains138]

It took 4 generations, but finally the PS brand is easy to develop games for.

I would like to assume that exclusive games will be brought to the consumer faster since development will not be as time consuming now. I'd like to think that. Time will tell I suppose.

[windblowsagain]

Arguing over ram.

PS4 has a better GPU coupled with a large amount of ram.

But when it comes down to it, it's about games,price,friends,etc.

[Supermax]

Exactly windblow