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Forums - Gaming Discussion - PS5 vs XSeX: Understanding the Gap

ironmanDX on 23 March 2020
CGI-Quality said:
ironmanDX said:
All these threads are just brining more attention to it. I can't recall one Xbox fan made thread really talking up the power discrepancy. We talk about it in the empire thread and what have you though.

I mean it's nice to have the more powerful console but guys... We don't really care that much. Just wait for the games, for the love of god.

Eh, I get why people are discussing it just like I got why people did it in past generations. Trying to eliminate the conversation because it bugs you means you care more about it then you'd like to admit. It's one of the reasons PC gamers sit back and point and laugh, because one minute it's fair game, and the next, you want it to end. Never mind how much bitchin' went on about how "under powered the PS4 and Xbox One were, so we shouldn't talk about them". Now, we have devices 'competent' (relatively) and people aren't free to discuss? Sounds unreasonable.

I applaud this topic and others like (so long as they aren't carbon copies), especially as it drives both discussion and traffic to the site. Particularly with everything going on in the world right now, a little tech talk hurts no one. Besides, the OP isn't trying to downplay or (up play) the difference. He's simply offering some perspective, and because these two devices are wildly different with a rather moderate (yes, moderate, it isn't as big as people make it out) contrast in power, it makes the chat that much more interesting.

Yeah, I am annoyed by it I suppose. I don't really care too much simply because not all information is out yet and even though we have some raw numbers I feel both systems have yet to reveal everything.

Still don't really care for the "but you did it first" type of responses though. We could go back forever on the you said, he said game and it would just be an inevitably pointless debate. I don't think we'll get real perspective until they have been released. I still feel like both companies have yet to reveal their full hand.



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ironmanDX on 23 March 2020
Fei-Hung said:
I have a question for you techy lot. Does audio processing take up a lot of RAM since the ps5 has its own processor for this?

Secondly, Cerny made a point where the audio processor can also be utilised for other processing needs if need be to offset workload. Do we know any tech details for the audio processor?

No. There is an audio processor in the XSX and if there wasn't it would more likely than not be CPU bound anyway. (To the best of my limited knowledge)

As for your second question... No idea. Do we have that information? Could it possibly be that more information about it has yet to be revealed?



Intrinsic on 23 March 2020

Here's a fun read on how exactly these SSDs work in the next gen consoles. Sorry if old or someone already put this up. 

There's a lot of confusion on why SSD is so important for next-gen and how it will change things.
Here I will try to explain the main concepts.
TL;DR fast SSD is a game changing feature, this generation will be fun to watch!

It was working fine before, why do we even need that?
No, it wasn't fine, it was a giant PITA for anything other than small multiplayer maps or fighting games.
Let's talk some numbers. Unfortunately not many games have ever published their RAM pools and asset pools to the public, but some did.
Enter Killzone: Shadowfall Demo presentation.
We have roughly the following:

Type Approx. Size, % Approx. Size, MB
Textures 30% 1400
CPU working set 15% 700
GPU working set 25% 1200
Streaming pool 10% 500
Sounds 10% 450
Meshes 10% 450
Animations/Particles 1% 45

*These numbers are rounded sums of various much more detailed numbers presented in the article above.

We are interested in the "streaming pool" number here (but we will talk about others too)
We have ~500MB of data that is loaded as the demo progresses, on the fly.
The whole chunk of data that the game samples from (for that streaming process) is 1600MB.
The load speed of PS4 drive is (compressed data) <50MB/sec (uncompressed is <20MB/sec), i.e. it will take >30sec to load that at least.

It seems like it's not that big of a problem, and indeed for demo it is. But what about the game?
The game size is ~40GB, you have 6.5GB of usable RAM, you cannot load the whole game, even if you tried.
So what's left? We can either stream things in, or do a loading screen between each new section.
Let's try the easier approach: do a loading screen
We have 6.5GB of RAM, and the resident set is ~2GB from the table above (GPU + CPU working set). We need to load 4.5GB each time. It's 90 seconds, pretty annoying, but it's the best case. Any time you need to load things not sequentially, you will need to seek the drive and the time will increase.
You can't go back, as it will re-load things and - another loading screen.
You can't use more than 4.5GB assets in your whole gaming section, or you will need another loading screen.
It gets even more ridiculous if your levels are dynamic: left an item in previous zone? Load time will increase (item is not built into the gaming world, we load the world, then we seek for each item/item group on disk).
Remember Skyrim? Loading into each house? That's what will happen.
So, loading screens are easy, but if your game is not a linear, static, theme-park style attraction it gets ridiculous pretty fast.

How to we stream then?
We have a chunk of memory (remember 500Mb) that's reserved for streaming things from disk.
With our 50MB/sec speed we fill it up each 10 sec.
So, each 10 sec we can have a totally new data in RAM.
Let's do some metrics, for example: how much new shit we can show to the player in 1 min? Easy: 6*500 = 3GB
How much old shit player sees each minute? Easy again: 1400+450+450+45=~ 2.5GB
So we have a roughly 50/50 old to new shit on screen.
Reused monsters? assets? textures? NPCs? you name it. You have the 50/50 going on.

But PS4 has 6.5GB of RAM, we used only 4.5GB till now, what about other 2GB?
Excellent question!
The answer is: it goes to the old shit. Because if we increase the streaming buffer to 1.5GB it still does nothing to the 50MB/sec speed.
With the full 6.5GB we get to 6GB old vs 3GB new in 1 minute. Which is 2:1 old shit wins.

But what about 10 minutes?
Good, good. Here we go!
In 10 min we can get to 30GB new shit vs 6GB old.
And that's, my friends, how the games worked last gen.
You're as a player were introduced to the new gaming moments very gradually.
Or, there were some tricks they used: open doors animation.
Remember Uncharted with all the "let's open that heavy door for 15sec?" that's because new shit needs to load, players need to get to a new location, but we cannot load it fast.

So, what about SSDs then?
We will answer that later.
Let's ask something else.

What about 4K?
With 4K "GPU working set" will grow 4x, at least.
We are looking at 1200*4 = 4.8GB of GPU data.
CPU working set will also grow (everybody wants these better scripts and physics I presume?) but probably 2x only, to 700*2 = ~1.5GB
So overall the persistent memory will be well over 6GB, let's say 6.5GB.
That leaves us with ~5GB of free RAM in XSeX and ~8GB for PS5.

Stop, stop! Why PS5 has more RAM suddenly?
That's simple.
XSeX RAM is divided into two pools (logically, physically it's the same RAM): 10GB and 3.5GB.
GPU working set must use the 10GB pool (it's the memory set that absolutely needs the fast bandwidth).
So 10 - 4.8 = 5.2 which is ~5GB
CPU working set will use 3.5GB pool and we will have a spare 2GB there for other things.
We may load some low freq data there, like streaming meshes and stuff, but it will hard to use in each frame: accessing that data too frequently will lower the whole system bandwidth to 336Mb/sec.
That's why MSFT calls the 10GB pool "GPU optimal".

But what about PS5? It also has some RAM reserved for the system? It should be ~14GB usable!
Nope, sorry.
PS5 has a 5.5GB/sec flash drive. That typically loads 2GB in 0.27 sec. It's write speed is lower, but not less than 5.5GB/sec raw.
What PS5 can do, and I would be pretty surprised if Sony won't do it. Is to save the system image to the disk while the game is playing.
And thus give almost full 16GB of RAM to the game.
2GB system image will load into RAM in <1 sec (save 2GB game data to disk in 0.6 sec + load system from disk 0.3 sec). Why keep it resident?
But I'm on the safe side here. So it's ~14.5GB usable for PS5.

Hmm, essentially MSFT can do that too?
Yep, they can. The speeds will be less sexy but not more than ~3sec, I think.
Why don't they do it? Probably they rely on OS constantly running on the background for all the services it provides.
That's why I gave Sony 14.5GB.
But I have hard time understanding why 2.5GB is needed, all the background services can run on a much smaller RAM footprint just fine, and UI stuff can load on-demand.

Can we talk about SSD for games now?
Yup.
So, let's get to the numbers again.
For XSeX ~5GB of "free" RAM we can divide it into 2 parts: resident and streaming.
Why two? Because typically you cannot load shit into frame while frame is rendering.
GPU is so fast, that each time you ask GPU "what exact memory location are you reading now?" will slow it down to give you an answer.

But can you load things into other part while the first one is rendering?
Absolutely. You can switch "resident" and "streaming" part as much as you like, if it's fast enough.
Anyway, we got to 50/50 of "new shit" to "old shit" inside 1 second now!
2.5GB of resident + 2.5GB of streaming pool and it takes XSeX just 1 sec to completely reload the streaming part!
In 1 min we have 60:1 of new/old ratio!
Nice!

What about PS5 then? Is it just 2x faster and that's it?
Not really.
The whole 8GB of the RAM we have "free" can be a "streaming pool" on PS5.

But you said "we cannot load while frame is rendering"?
In XSeX, yes.
But in PS5 we have GPU cache scrubbers.
This is a piece of silicon inside the GPU that will reload our assets on the fly while GPU is rendering the frame.
It has full access to where and what GPU is reading right now (it's all in the GPU cache, hence "cache scrubber")
It will also never invalidate the whole cache (which can still lead to GPU "stall") but reload exactly the data that changed (I hope you've listened to that part of Cerny's talk very closely).

But it's free RAM size doesn't really matter, we still have 2:1 of old/new in one frame, because SSD is only 2x faster?
Yes, and no.
We do have only 2x faster rates (although the max rates are much higher for PS5: 22GB/sec vs 6GB/sec)
But the thing is, GPU can render from 8GB of game data. And XSeX - only from 2.5GB, do you remember that we cannot render from the "streaming" part while it loads?
So in any given scene, potentially, PS5 can have 2x to 3x more details/textures/assets than XSeX.
Yes, XSeX will render it faster, higher FPS or higher frame-buffer resolution (not both, perf difference is too low).
But the scene itself will be less detailed, have less artwork.

OMG, can MSFT do something about it?
Of course they will, and they do!
What are the XSeX advantages? More ALU power (FLOPS) more RT power, more CPU power.
What MSFT will do: rely heavily on this power advantage instead of the artwork: more procedural stuff, more ALU used for physics simulation (remember, RT and lighting is a physics simulation too, after all).
More compute and more complex shaders.

So what will be the end result?
It's pretty simple.
PS5: relies on more artwork and pushing more data through the system. Potentially 2x performance in that.
XSeX: relies more on in-frame calculations, procedural. Potentially 30% performance in that.
Who will win: dunno. There are pros and cons for each.
It will be a fun generation indeed. Much more fun than the previous one, for sure.



Intrinsic on 23 March 2020

Fei-Hung said:
I have a question for you techy lot. Does audio processing take up a lot of RAM since the ps5 has its own processor for this?

Secondly, Cerny made a point where the audio processor can also be utilised for other processing needs if need be to offset workload. Do we know any tech details for the audio processor?

Not a lot of RAM, but t takes up some. And it also mostly depends on what kinda audio we are talking about.

Think of audio like textures. Just bigger files but fewer of them compared to textures. They have to be moved around too, just like textures. They have to be "mapped" too, just like textures. They have to be kept in RAM too, just like textures.

The PS5s sound chip, its more about handling the complex sound systems sony is trying to push for next-gen. As for the sound processor being used for other stuff... well, its pretty much a stripped down SPU o I guess it could be used for some stuff. 



KLAMarine on 23 March 2020

XSeX



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Moonhero on 23 March 2020

I'm not too big into trying to piece together which one will do what in terms of graphics. I am just pumped for PS5. That crazy audio thing they are doing with it sounds like it will make games really interesting going forward.



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Intrinsic on 23 March 2020
Moonhero said:
I'm not too big into trying to piece together which one will do what in terms of graphics. I am just pumped for PS5. That crazy audio thing they are doing with it sounds like it will make games really interesting going forward.

It sounds great too, and if its not that they gave up some space for it in their APU silicon budget I wouldn' take it as anything more than the kinda luff these companies talk about but never actually do... eg the cloud.

It should at the very least do wonders for VR though. Speaking of VR I found it strange sony didn't mention VR at all during their PS5 deep-dive. 



starcraft on 23 March 2020
DonFerrari said:
ironmanDX said:

I'm talking about the XSX and PS5.

Not really looking for... "But you guys did it first" type of responses.

I could also retort with talk about The cell but that was so many years ago are most of the users even likely to be the same? Probably not.

Sorry, I thought you were saying that back when Xbox was the one with less power the Xbox users didn't made a lot of threads defending it.

If we are talking about PS5, yes I have only seem Sony fans making ones to defend or diminish the difference but not a single one attacking PS5 (at least in VGC). Also several of the Xbox fans commenting are just saying the very obvious that Xbox is more powerful but PS5 is strong enough to show a good performance.

That is probably the fairest way I have seen you put this.

Yes, its obvious there is a power discrepancy. We'll have to wait for some games to see whether the Xbox has a moderate or large advantage in what it can achieve graphics or gameplay-wise.



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Intrinsic on 23 March 2020
starcraft said:

That is probably the fairest way I have seen you put this.

Yes, its obvious there is a power discrepancy. We'll have to wait for some games to see whether the Xbox has a moderate or large advantage in what it can achieve graphics or gameplay-wise.

I think its obvious how and where the advantages would show themselves. All we have to do is look at the PS4/XB1 and the pS4pro/XB1X. Then take into account just how different those consoles were from each other respectively.

The "gap" or "power difference" people are alluding to, while there, is nowhere even close to as significant as any of the aforementioned comparisons.

A simple way to ut it, not only does the upcoming gen represent the smallest gap ever between two PS vs Xbox consoles at launch, the bar has collectively been set so high that it gets really hard to spot the difference. For reference, watch the RE3/Doometernal digital foundry videos. Look at the XB1X vs the PS4pro. Then remember that the XB1X has a 50% compute advantage, 50% RAM bandwidth advantage and 50% More RAM.



Intrinsic on 23 March 2020
zero129 said:
Intrinsic said:

Oh.. and with regards to their rated clocks? They will hit those clocks whenever they are needed to hit them. Especially the PS5. It may seem hard to believe, but its actually easier for thePS5 to hit its 2.2Ghz clock than it would be for the XSX to ht its 1.8Ghz clock. Long story...

Now hitting max load is a completely different mater. Which is what I believe you ar talking about. Yes, its harder keeping more CUs busy and running efficiently and that is a benefit of the choice sony made with their CU count.

Please do explain how you figure XSX will have a harder time hitting their clocks and how more CU's and shaders = worse performance id love to hear it...

Sorry, didn't see this. 

First off, I never said more CUs (which are shaders) = worse performance. I said XSX would have a harder time hating that 1825Mhz lock than the PS5 would have hitting its 2230Mhz clock. Saying something will have a harder time is not the same thing as saying t can't do it...unless that's what you want to see it as. But it's not the same thing though. I mean I think even in what you quoted I literally said "they will hit those clocks whenever they are needed to hit them".

The reason is simple and obvious really... the size of the chip. Its simply easier clocking a smaller chip higher than it is clocking a larger chip high. And its harder dissipating heat from larger chip than it is from smaller ones. Look at every single GPU out there, or CPU, it's not a coincidence that the ones with really high core counts run at slightly lower clock speeds.

And with regard to the other stuff I posted.. you and others may call it one guys opinion, but it doesn't mean he said is no true. If you take the information available, his depiction of things is literally the benefits that the SSD would bring. And how it can be utilized. I obviously agree with his explanation, which is why I posted it. You don't have to agree with it obviously.