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[travisbickle]

I don't think anyone ever forgot. Initially there was concern that Sony would be blown away if they only had 2GB RAM (very early rumours). Then the bump to 4GB put us in a 'no mans land' of trying to dissect 4GB fast Vs 8GB fast, plus whether less ram hindered the ability of PS4 to actually make use of its more powerful (on paper) GPU.


TBH, now they both seem fairly level in terms of ram. If Xbox is really 102GB/s then that is very fast for DDR and adding in the ESRAM should give similar levels of performance. That is reassuring more than 'omg sony rox'

Is there DDR3 available at those speeds? or is this possibly custom-made for the system?

 

[KidBeta]

Is there DDR3 available at those speeds? or is this possibly custom-made for the system?

the DDR3 in Durango is 68GB/s the top speed for DDR3 as rated by JEDEC

the eSRAM on the other hand is 102GB/s, he's getting confused between the two.

 

[Gemüsepizza]

I don't think anyone ever forgot. Initially there was concern that Sony would be blown away if they only had 2GB RAM (very early rumours). Then the bump to 4GB put us in a 'no mans land' of trying to dissect 4GB fast Vs 8GB fast, plus whether less ram hindered the ability of PS4 to actually make use of its more powerful (on paper) GPU.


TBH, now they both seem fairly level in terms of ram. If Xbox is really 102GB/s then that is very fast for DDR and adding in the ESRAM should give similar levels of performance. That is reassuring more than 'omg sony rox'

The Xbox 3 is supposed to have 8GB DDR3 RAM with 68GB/s, not 102GB/s - that's the speed of the 32 MB eSRAM. And they are certainly *not* on the same level if those rumors are true.

 

[IHaveCandy]

Wasn't there a rumor that the PS4 would have 16 GB flash memory? I assume that is partly where the OS is stored. Couldn't they use that space for constantly recording instead of the HDD or RAM?

 

[JonathanPower]

a DVR is not a console, HDD trashing will be a real issue if they record the the HDD.

http://en.wikipedia.org/wiki/Thrashing_(computer_science)

If they are doing the same thing, how can recording not affect a DVR but the PS4? It does not make sense. I mean, even cell phones can record straight to memory without any problem. This really seems a no issue.

 

[KidBeta]

If they are doing the same thing, how can recording not affect a DVR but the PS3? It does not make sense. I mean, even cell phones can record straight to memory without any problem. This is really seems a no issue.

I mean that the trashing will be a issue because the PS4 is probably going to want way better performance out of the HDD then a typical DVR is, nothing stopping it from recording to ram though.

 

[IHaveCandy]

Recording to RAM seems wasteful.how much RAM are we talking about? Is it a secondary smaller pool of RAM for the secondary chip? The secondary chip is a SoC right? Maybe it has its own RAM for this.

 

[Pristine_Condition]

H3XAntiStyle: Dedicated video encoding/decoding chips doing the tasks you're talking about are in every video camera. That's why even a cellphone camera Or a little GoPro type device works and can process 1080p video in these devices. Those devices don't have tons of RAM, if they have any at all. It's stream processing, and the memory needed for the task would be some very fast local store on the video chip itself (SRAM) or next door (DRAM) and it uses a pretty tiny amount. (IIRC, it's around 256Kb (and yes...that small "b" is correct--it's kilobits...) for reference frame storage these days in the chips found in 1080p/60 capable cameras.)

So, in all likelihood, since we know the PS4 has one of these dedicated chips onboard, the task of encoding your 15minute gameplay video or the video you stream to your live video channel won't even touch the GDDR5, save for whatever interaction you do in the OS.

So you're telling me that it can take Frame A, B, and C, figure out between them where the image similarities are to compress them in terms of what-to-change data (don't know the technical term), and then compress between the pixels, all without those frames ever having to go to RAM?

That's not precisely the process, but yep. It never has to go to RAM. In fact these little processors are so fast at doing what they do (since that's all they are designed to do) that messing about in the general RAM pool would just complicate and quite probably slow down the process.

 

[Tobiasboon]

I mean that the trashing will be a issue because the PS4 is probably going to want way better performance out of the HDD then a typical DVR is, nothing stopping it from recording to ram though.

The PS3 already can record TV to the HDD while gaming with no real impact, I don't see any reason why the PS4 couldn't unless I'm totally missing something?

 

[Hydrogen Bluebird]

The PS3 already can record TV to the HDD while gaming with no real impact, I don't see any reason why the PS4 couldn't unless I'm totally missing something?

Do you guys think the tv recording while playing feature would be included in the PS4?

 

[KidBeta]

The PS3 already can record TV to the HDD while gaming with no real impact, I don't see any reason why the PS4 couldn't unless I'm totally missing something?

Interesting, so its doable but its certainly not ideal.

 

[Brad Grenz]

Interesting, so its doable but its certainly not ideal.

You're vastly overstating the effect 1MB per second of traffic would have on the HDD. If it was a problem they could still buffer 20MB into RAM which gives them 20 seconds in which to find an open write window to retire the stream to the HDD (which would take less than a second). To suggest they would need to buffer the entire 15 minutes in RAM is beyond ludicrous.

 

[KidBeta]

You're vastly overstating the effect 1MB per second of traffic would have on the HDD. If it was a problem they could still buffer 20MB into RAM which gives them 20 seconds in which to find an open write window to retire the stream to the HDD (which would take less than a second). To suggest they would need to buffer the entire 15 minutes in RAM is beyond ludicrous.

Im thinking more about the heads on the hdd, but I could be wrong.

 

[BradleyLove]

Im thinking more about the heads on the hdd, but I could be wrong.

PS4 could have an HDD partition dedicated to storing recorded video. As its always a maximum of 15 mins, PS4 simply rewrites over the same blocks.

At worst, this partition becomes defragmented but seeing as its for recording video, no harm done.

 

[KidBeta]

PS4 could have an HDD partition dedicated to storing recorded video. As its always a maximum of 15 mins, PS4 simply rewrites over the same blocks.

At worst, this partition becomes defragmented but seeing as its for recording video, no harm done.

Yeah but then if the heads on the drives are constantly moving back to write to the video partition then the performance degrades.

 

[sono]

Yeah but then if the heads on the drives are constantly moving back to write to the video partition then the performance degrades.

How much harddrive reading will PS4 games need to do with all that ram ?

i.e in game the harddrive i/o may only be related to recording gameplay.

Between gameplay (e.g next chapter or major game segment) it loads from hardrive or bluray, but you dont record the loading).

Same thing with save game progress.

Overall I dont see why they would be contention.

Even then, I am sure the OS will manage same to give gameplay priority if conflicting requests come in.

Also: in Mark Cerny I trust.

 

[pharmboy044]

So I read that GDDR5 is a waste for the OS. Is it possible that Sony could use something else for the OS and leave the entire GDDR5 for the devs?

 

[Sendou]

So I read that GDDR5 is a waste for the OS. Is it possible that Sony could use something else for the OS and leave the entire GDDR5 for the devs?

So what you're saying is that they should include even more RAM?

 

[SSM25]

So I read that GDDR5 is a waste for the OS. Is it possible that Sony could use something else for the OS and leave the entire GDDR5 for the devs?

Overkill maybe, waste? No

 

[Brad Grenz]

Yeah but then if the heads on the drives are constantly moving back to write to the video partition then the performance degrades.

Modern hard drives are well equipped for this. To go back to the DVR example, I have a Hopper in my house. It can simultaneously record up to 6 HD channels while playing back 4 HD recordings from a single hard drive. Any performance "degradation" from PS4 writing a 1MB per second video file to disk either constantly, or in bursts from a small memory buffer, would be measured in single digit percentages, if it even surfaces at all.

So I read that GDDR5 is a waste for the OS. Is it possible that Sony could use something else for the OS and leave the entire GDDR5 for the devs?

Whoever said that is an idiot.

 

[Durante]

So I read that GDDR5 is a waste for the OS. Is it possible that Sony could use something else for the OS and leave the entire GDDR5 for the devs?

No, because there isn't anything else. The whole point of the architecture is that you only need one RAM pool.

 

[AgentP]

It's hard to figure out why the thread take these weird turns. I'm guessing KidBeta is fishing for something negative. These are not modern technical issues, they were solved years ago with lesser hardware.

 

[KidBeta]

K that might work

 

[i-Lo]

Pertaining to Memory Bus Width, is it 256-bit?

 

[dr_rus]

Pertaining to Memory Bus Width, is it 256-bit?

Yes if the 176 GB/second figure is accurate.

 

[IrrelevantNotch]

So I read that GDDR5 is a waste for the OS. Is it possible that Sony could use something else for the OS and leave the entire GDDR5 for the devs?

Should've gone with 4gb GDDR5 and 2gb DDR3

 

[ghst]

Overkill maybe, waste? No

no. overkill would be if it had the bandwidth of GDDR5, the latency of DDR3 and a suitably wide bus.

 

[TKM]

Should've gone with 4gb GDDR5 and 2gb DDR3

Oh hell no. Costs more in the long run for less performance, and increased development headaches.

 

[Takuya]

So I read that GDDR5 is a waste for the OS. Is it possible that Sony could use something else for the OS and leave the entire GDDR5 for the devs?

The OS may not be able to take full advantage of the GDDR5 but it's not like it will bog down system performance. Having one pool of unified memory is best in this case, splitting it for the OS just complicates things for nothing.

 

[stryke]

Discussing about the PS4 in another forum, someone comes along and says this:

I was thinking about about the PS4's GDDR5 memory.

174GB/s of bandwidth. I think it's a load of crap and another case of Sony providing us inflated theoretical best case numbers.

GDDR5 moduels I/O is 32bit. 16bit is for reads and 16bit for writes. In many high end PC GPUs the GDDR5 modules bus is split. There's two memory controllers, one handles the 16bit input for writes, and the other controller handles the 16bit output for reads.

The downside of the above of course is that you're doubling up for the most part on busses, running two 16bit busses instead of one 32bit. You're also running two memory controllers, one for reading and one for writing. These two factors significantly increase the manufacturing costs, as you have to double the memory controllers and busses increasing die size, complexity, and PCB layout.

In cheaper GPUs there's simply one memory controller, and it has to handle reads and writes. It cannot read and write at the same time, it can only done one at a time. This design is a lot cheaper, simplier, and cost effective to manufacturer, but the downside is bandwidth is significantly reduced.

I doubt very very much the PS4's GDDR5 is running with its bus split to allow for simultanious reads and writes.

The 174GB/s would be the theoretical max, in a ideal read or write only situation. In the real world when you have to factor in real I/O use, overheads, memory controller efficiency, i doubt the PS4's GDDR5 can pull anywhere near 174GB/s

Which also makes sense given the GPU is stated to be only 1.8 teraflops.

Is he correct in saying that? (Mind you I don't what his background is in regards to tech).

edit: I don't know much about this stuff, but gut feeling tells me clamshell design negates his complaints?

 

[Wishmaster92]

That is very interesting stryke, i would also like to know.

 

[CLEEK]

Of course 176GB/s is the theoretical maximum. That has nothing to do with being misleading, or in anyway inaccurate, but just how you define bandwidth. Like the 1.84 TFLOPS is also the theoretical max performance of the GPU and the 102 GFLOPS for the CPU. As is the listed read speed of the 6X BD drive. As is... you get the idea.

No computing system ever runs at 100% efficiency across all components. But each component will have a clearly defined spec and max capacity.

The points raised in that post can also be applied to every computer and console ever.

 

[AgentP]

Sounds like he is mangling clamshell mode, which is not performance related.

The benefit of clamshell mode is that users are able to quickly react on changing market conditions by easily creating new product
variations. E.g., by taking the same component from the inventory, utilizing the same controller, PCB layout and memory channel
width, the user can decide on the actual framebuffer size at a very late stage of the manufacturing process by
• either populating only one side of the PCB and configuring the GDDR5 to x32 mode, which results e.g. in a 1GB framebuffer
by using 8 pieces of 1Gbit with a 256-bit wide memory interface at the controller;
• or populating both sides of the PCB and configuring the GDDR5 to x16 mode, which results e.g. in a 2GB framebuffer by using
16 pieces of 1Gbit with a 256-bit wide memory interface at the controller.
Clamshell mode has no performance penalty because it preserves the point-to-point connection on the high-speed data bus. The
shared address and command interface can easily be connected by vias in the PCB and the use of mirror function mode which lets
these pins appear at the exact opposite locations.

www.elpida.com/pdfs/E1600E10.pdf

 

[Pristine_Condition]

Made this for you, Gaming-AGE:

 

[BurnOutBrighter]

This might a stupid question but it's been bugging me. It's about live streaming on the PS4 via Ustream. You don't need a PS4 to be able to watch a person playing and streaming from their PS4, is that correct? So you can watch on a PC, tablet, or anything with the internet as long as you can get to Ustream's website, is that correct. Just making sure because I'm actually pretty excited about this feature(I watch people playing videos games a bit too much as you can guess).

Correct.

 

[SuperEpicGuy]

Not really. If it was up to him we would of got 20GB of GDDR10, 16 cell processors, and 32 SPE's. lol.

Yep. Like mentioned in my last post, people have changed their attitude towards PS4's RAM quick. It's really rediculous.

Does anyone know why he/she got banned? I am looking through the posts and don't see anything that stands out. Just wondering to make sure to not do the same mistake.

To keep on topic, how much would that extra ram cost? Maybe like $30-40 tops?

 

[BlastProcessing]

oops. Total post missfire. My bad.

 

[Perkel]

wha wha wha. total post missfire.

Double missfire then.

 

[Didly]

For clarity, my 680 has how much GDDR5? 2 or 6GB?

 

[Zombie James]

For clarity, my 680 has how much GDDR5? 2 or 6GB?

2GB.