Xsx BC mode doesn't use any RDNA 1/2 features / improvements.

[arsene_P5]

So... boost mode?

Wasn't Xbox Twitter celebrating that they didn't have it?

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Boost mode is basically just Sony's term for brute forcing games by allocating them all the available CPU and GPU power. It's the same thing.

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Right about the CUs, but the underlying concept is pretty much the same. Just leveraging the addition al resources of the machine to allow games that have unblocked/scalable engines to take advantage of the additional horsepower.

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No boost mode as used by PS4 Pro for example is nothing else than upclocking the GPU frequency. Xbox solution is different and more complicated to do, because it can use all the hardware power including more CU's. Thus it's literally not a boost mode and not the same concept.

To the end consumer, it's the same thing.

Existing games running at closer to their target frame rates and resolutions.



It's basically boost mode. Frame rates are a boost.

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Nope, unless you think running Knack at 40ish FPS compared to 60FPS is the same experience. PS4 Pro couldn't use half of its power in Boost mode, thus the improvements were really small. While a Pro using 36CU at 911mhz (as evident by the knack pro patch) could run knack easily at 60FPS.

We can except the same use case for PS5 ? GCN compatibility mode with full power ?

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Current situation seems to be the following...

• PS4 legacy mode: 16CU at ~800mhz
• Pro legacy mode: 36CU at 911mhz
• Native mode: 36 CU ~2,3 GHz.

PS5 has those three modes and it will depend on the game, which mode is used. Legacy won't bring any enhancements with the exception of better load times.

 

[Joo]

No boost mode as used by PS4 Pro for example is nothing else than upclocking the GPU frequency. Xbox solution is different and more complicated to do, because it can use all the hardware power including more CU's. Thus it's literally not a boost mode.

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It's still essentially the same thing. Both consoles have a "legacy mode" which uses the logic and feature sets of GCN by mimicking current gen architecture to run current gen games. The games just benefit from all around better specs resulting in better fps, higher res etc with certain games.

This is essentially how Cerny explained it and doesn't really seem differ from Xbox, and at least I can't find any information that says otherwise.

 

[crazillo]

Honestly, this is kind of a non-news to me because this was totally expected. I'm excited for the auto-HDR feature though!

 

[Kalasai]

Current situation seems to be the following...

• PS4 legacy mode: 16CU at ~800mhz
• Pro legacy mode: 36CU at 911mhz
• Native mode: 36 CU ~2,3 GHz.

PS5 has those three modes and it will depend on the game, which mode is used. Legacy won't bring any enhancements with the exception of better load times.

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I hope the native mode will be the more used and legacy only for problematic games.

 

[Naner]

While this is true, I expect some of the slight performance dips might get smoothed out in time. Remember, they constantly update the emulator performance in general and on a title by title basis. Halo Reach was terrible when it was enabled but it has been fixed. XSX is a new albeit similar/familiar architecture so I expect the performance to improve even more as time goes by and the BC team work more on the system.

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This time there's no emulation going on, it's just a compatibility mode. Kind of similar to what the Wii and Wii U had for BC, but taking advantage of the available horsepower instead of throttling.

 

[arsene_P5]

It's still essentially the same thing. Both consoles have a "legacy mode" which uses the logic and feature sets of GCN by mimicking current gen architecture to run current gen games. The games just benefit from all around better specs resulting in better fps, higher res etc with certain games.

This is essentially how Cerny explained it and doesn't really seem differ from Xbox, and at least I can't find any information that says otherwise.

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It's not essentially the same thing, because all games get the full power of the Xbox Series X (excluding RDNA2 enhancements). There are no legacy modes, which turn the console via downclocking and not using all CU into a Xbox One S/X.

It should be obvious old games not developed for variable rate shading and so on can't use it in BC. Native mode on PS5 is very similar as you get 36CU at those PS5 clockspeed. But as mentioned in the tweet by Xbox, Sony has as shown in the deep dives the legacy modes, which don't utilize all the hardware power to ensure compatibility. As a user you won't be getting any improvements compared to PS4/Pro in resolution or framerate running in these modes. That's a stark difference.

TLDR:

• Xbox has one mode. PS5 has three modes and one of those is similar to Xbox BC, while the two others will essentially turn your PS5 into PS4/Pro level consoles.
• Boost mode in the Xbox tweet refers to PS4 Pro boost mode, which was a simple GPU overclock. That's not the same as Xbox BC solution.

 

[Joo]

It's not essentially the same thing, because all games get the full power of the Xbox Series X (excluding RDNA2 enhancements). There are no legacy modes, which turn the console via downclocking and not using all CU into a Xbox One S/X.

It should be obvious old games not developed for variable rate shading and so on can't use it in BC. Native mode on PS5 is very similar as you get 36CU at those PS5 clockspeed. But as mentioned in the tweet by Xbox, Sony has as shown in the deep dives the legacy modes, which don't utilize all the hardware power to ensure compatibility. As a user you won't be getting any improvements compared to PS4/Pro in resolution or framerate running in these modes. That's a stark difference.

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Well yeah, but we don't actually even know how many games will need to rely on downclocking. The difference seems to be there only because Sony isn't as far along with BC as MS is with testing, not because the actual process is different.

If I'm reading what Cerny has said correctly, every game Sony has tested will run with full clocks. While the amount of games utilising the full power with GCN's logic will grow over time, it will of course almost certainly be smaller on PS5 at launch than on XSX. Still, the actual way of how this is achieved in a sense is exactly the same as with Xbox. If this is not the case, I just don't understand the difference.

 

[dmix90]

So.... uhhh is it "just" Vega 64 then? Or there is a better equivalent on PC for unpatched XSX BC performance?

 

[Karlinel]

But...isn't this common sense, since those are 2 different architectures and the games were built for just one of them?
At least the games are boosted as all hell, I wish DF will do this with series S too so I can see what I'll get. Even tho, if it just uses TF counts, series S from One X would be basically unchanged, right?

 

[dmix90]

Sekiro

This is on Max settings and at full 4K though, Xbox One X running this game at ~1800p and

these settings

 

[Jraphics Horse]

But...isn't this common sense, since those are 2 different architectures and the games were built for just one of them?
At least the games are boosted as all hell, I wish DF will do this with series S too so I can see what I'll get. Even tho, if it just uses TF counts, series S from One X would be basically unchanged, right?

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Going from One X to Series S? Not exactly. For one thing, some One X games had One X specific features, like the headlight shadows in FH4, if the games don't get patched they will just run at One S settings, but with more performance available.

 

[neoak]

Well yeah, but we don't actually even know how many games will need to rely on downclocking. The difference seems to be there only because Sony isn't as far along with BC as MS is with testing, not because the actual process is different.

If I'm reading what Cerny has said correctly, every game Sony has tested will run with full clocks. While the amount of games utilising the full power with GCN's logic will grow over time, it will of course almost certainly be smaller on PS5 at launch than on XSX. Still, the actual way of how this is achieved in a sense is exactly the same as with Xbox. If this is not the case, I just don't understand the difference.

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Sony BC doesn't do any enhancements either, like Auto HDR. It's just trying to emulate the old hardware.

Literally shown in then presentation, 3 modes: PS4, PS4 Pro because of Pro enhancements, and PS5.

Xbox allows the System to do extra steps to add stuff. The other is not better than the PS4 Pro using Boost mode because they don't have the abstraction layer. Don't say the work is similar because the time spent on Xbox BC is in the order of magnitudes larger as what Sony has spent making theirs BC.

Digital Foundry already said there is a supposed framerate doubling mode that will be revealed soon. Sony doesn't have anything of that.

 

[Joo]

Sony BC doesn't do any enhancements either, like Auto HDR. It's just trying to emulate the old hardware.

Literally shown in then presentation, 3 modes: PS4, PS4 Pro because of Pro enhancements, and PS5.

Xbox allows the System to do extra steps to add stuff. The other is not better than the PS4 Pro using Boost mode because they don't have the abstraction layer. Don't say the work is similar because the time spent on Xbox BC is in the order of magnitudes larger as what Sony has spent making theirs BC.

Digital Foundry already said there is a supposed framerate doubling mode that will be revealed soon. Sony doesn't have anything of that.

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Just.. I'm not saying the BC in both is exactly the same, but the actual underlying process still seems to be exactly the same. Xbox having auto-HDR or frame rate doubling are great things, but those aren't the point here nor do they in any way change what I'm trying to say. And what are those other extra steps the system just allows to add stuff?

With PS5 there's PS4 and Pro modes, which might be used with a certain game if Sony hasn't checked and approved that the native PS5 specs do not cause issues. We don't actually even know if this is how it is, or how something like PS4 Pro mode exactly works.

Cerny just says that the boost to BC games is massive this time around and so the checking needs to done on a title by title basis, exactly like with Xbox. When Sony also says that BC games will get improved frames, higher res etc with certain games, I just don't see how these approaches differ in any way at heart. Why would they need to check anything if everything would just work exactly like with PS4 by mimicking those specs? There wouldn't be any need.

I'm just not trying to debate which console has better BC like you seem to think.

 

[Wereroku]

Sony BC doesn't do any enhancements either, like Auto HDR. It's just trying to emulate the old hardware.

Literally shown in then presentation, 3 modes: PS4, PS4 Pro because of Pro enhancements, and PS5.

Xbox allows the System to do extra steps to add stuff. The other is not better than the PS4 Pro using Boost mode because they don't have the abstraction layer. Don't say the work is similar because the time spent on Xbox BC is in the order of magnitudes larger as what Sony has spent making theirs BC.

Digital Foundry already said there is a supposed framerate doubling mode that will be revealed soon. Sony doesn't have anything of that.

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No they didn't. They were talking about frame rate doubling upgrades. It's the same thing MS has already talked about where they will go back and upgrade select titles to run beyond the original specs. Richard said his dream would be a frame rate doubling mode like the Auto HDR not that MS already has it.

 

[Garrison]

Old software doesn't take advantage of hardware features released afterwards. Wow.

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Pretty much like it works everywhere right.

I remember back in the day so many games had released for with dual-core cpus in mind, never took/will take advantage of any quad-core or better components.

They will always run better on newer hardware because the power they used back in the day was surpassed a long time ago but this is so obvious they're not going to take full advantage of newer components unless patched.

 

[jroc74]

This explains why XSS runs games in 1S mode. Without IPC gains its a flat 4TF GCN machine for BC games.

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Damn, now it makes sense.

 

[jroc74]

I hope the native mode will be the more used and legacy only for problematic games.

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That's exactly what Cerny was saying, the top 100 games tested, he was talking about the PS5 native mode running PS4 games. Why would be be talking about the modes that mimic exactly the PS4 and the Pro?

He clarified it later saying those modes are 'kept in the back pocket,' while they continue to work on BC.

Some of us kept trying to explain this. Maybe it's more clearer now....

www.usgamer.net/amp/ps5-backward-compatibility-cerny-legacy-modes-digital-foundry

The source is the DF article.

 

[Kalasai]

That's exactly what Cerny was saying, the top 100 games tested, he was talking about the PS5 native mode running PS4 games. Why would be be talking about the modes that mimic exactly the PS4 and the Pro?

He clarified it later saying those modes are 'kept in the back pocket,' while they continue to work on BC.

Some of us kept trying to explain this. Maybe it's more clearer now....

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Thanks for the explaination :) I have to admit, i was a little confuse about this. Now is perfectly clear.

 

[Muitnorts]

The Series X BC so far looks incredibly impressive.
I'm interested to see how the Series S compares, as that's the one I'm getting.

 

[Masterz1337]

Halo 5? That isn't on PC

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The forge mode is and it can really be turnt up to 11 graphically

 

[GraceOfGod]

It really is fun watching the same people tying themselves into knots to downplay the work MS is doing with BC. I thought the digital foundry video showed great work, and I only expect it to get better given MS's dedication to it so far.

 

[III-V]

Damn, now it makes sense.

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Still more than 2X the GCN TF of the OneS

 

[Chick3n]

Cerny just says that the boost to BC games is massive this time around and so the checking needs to done on a title by title basis, exactly like with Xbox. When Sony also says that BC games will get improved frames, higher res etc with certain games, I just don't see how these approaches differ in any way at heart.

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Because the PS5 boost mode needs to be checked and probably manually enabled by Sony. Microsoft's applies to every single game no matter what. That's what Microsoft was saying by their no boost mode Tweet.

Series X: every BC game runs at 12 TF
PS5: some BC games run at 1.8 TF, some at 4.2 and some at 10.4 TF

It's a fundamental difference between the consoles BC implementations. The PS5 design was dictated by the need to match the PS4 and PS4 Pro CU counts to ensure compatibility. Microsoft doesn't have that limitation.

If Sony can get the boost mode working on enough games the end result will be the same, but it's still a clear difference between how the machines handle BC games.

 

[Joo]

Because the PS5 boost mode needs to be checked and probably manually enabled by Sony. Microsoft's applies to every single game no matter what. That's what Microsoft was saying by their no boost mode Tweet.

Series X: every BC game runs at 12 TF
PS5: some BC games run at 1.8 TF, some at 4.2 and some at 10.4 TF

It's a fundamental difference between the consoles BC implementations. The PS5 design was dictated by the need to match the PS4 and PS4 Pro CU counts to ensure compatibility. Microsoft doesn't have that limitation.

If Sony can get the boost mode working on enough games the end result will be the same, but it's still a clear difference between how the machines handle BC games.

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I don't mean to be rude, but surely you don't seem to know that in a way MS has also "manually enabled" the games by testing them. They've confirmed this is the case, have just done it much longer than Sony and because of that, are much further along.

MS themselves back-pedalled a little a couple months ago by saying they can't fully guarantee that every single current gen game will work, but that's their intent and that most will have benefits on the new console. For 360 and original Xbox games, there's a list of the compatible ones. That's because they haven't tested everything.

Now as we basically have a confirmation that both consoles handle BC in the same way by mimicking current gen's GCN architecture, that essentially means that at their core they work the same way, and this is also why MS tweet is bit misleading. They just can say that because it basically works that way in most cases, because they've already tested most of the games.

It'll just take longer for Sony to get to the same position + as of now they don't have any auto hdr or other additional software benefits. This doesn't mean that they couldn't add something like this if they wanted. I don't mean this in any way as a competition between platforms.

 

[litebrite]

I don't mean to be rude, but surely you don't seem to know that in a way MS has also "manually enabled" the games by testing them. They've confirmed this is the case, have just done it much longer than Sony and because of that, are much further along.

MS themselves back-pedalled a little a couple months ago by saying they can't fully guarantee that every single current gen game will work, but that's their intent and that most will have benefits on the new console. For 360 and original Xbox games, there's a list of the compatible ones. That's because they haven't tested everything.

Now as we basically have a confirmation that both consoles handle BC in the same way by mimicking current gen's GCN architecture, that essentially means that at their core they work the same way, and this is also why MS tweet is bit misleading. They just can say that because it's basically works that way in most cases because they've tested it.

It'll just take longer for Sony to get to the same position + as of now they don't have any auto hdr or other additional software benefits. This doesn't mean that they couldn't add something like this if they wanted. I don't mean this in any way as a competition between platforms.

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It doesn't work the same way because there are fundamental differences such as Xbox One being run as a virtual machine.
PowerThroughLov explained it best:

Have you ever heard of 'coding to the metal'? Its the idea of writing software code that runs directly on the underlying hardware - there is no middle man (software) between the code you write and the hardware it runs on. This allows for better performance as there is no overhead. This is why consoles often run better than a similar PC - they can optimize more. The downside is that the game is written for one very specific piece of hardware and cannot run elsewhere. This is why emulators exist - they have to emulate the hardware exactly as that's the only way the software can run.

For the Xbox One, Microsoft changed this. Instead of developers coding to the Xbox One hardware, they created a Virtual Machine that games ran in. The games coded to this Virtual Machine, and the Xbox then translated these virtual machine calls into hardware calls to run on the device. The actual 'system' the games ran on was a virtualized one that does not actually exist in hardware. The downside of this is there is a very slight performance penalty (very slight on a console since you can optimize it quite well). The upside is that you can easily run games on different hardware - you just have to create a new codebase that can translate the virtual machine calls to the native hardware code.

The Xbox One 'hardware' doesn't exist. Its fake (virtualized). This is why its so easy for Microsoft to make games run so well on different hardware - they only have to implement one single system layer to make every single game work. As long as they properly handle all calls the virtualized system makes to the hardware, they are compatible. This is why the Xbox One X has such a different architecture to the base Xbox One (no more ESRAM) yet still runs games no problem. Whereas the PS4 Pro has the occasional issue running base PS4 games (the games are talking to the PS4 Pro hardware directly, and the hardware is physically different).

Its costly and hard to make a good virtualized system though (otherwise everyone would do it).

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[Dictator]

If this is true, wouldn't it mean in some respects it could perform better than the one x? I cannot find a source right now but for some reason I want to say back compat on the one x was limited to using around 3 teraflops. Maybe I am wrong in that but I swear I remember reading that somewhere.

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I think that is indeed true.

 

[DukeBlueBall]

Sekiro

This is on Max settings and at full 4K though, Xbox One X running this game at ~1800p and

these settings

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Vega is a bit more advanced than the GCN in one X.

Vega 7 has a huge bandwidth advantage over almost everything on the market.

I think a Vega 64 stock clock is probably the closest comparison for Xsx in BC mode.

 

[arsene_P5]

For 360 and original Xbox games, there's a list of the compatible ones. That's because they haven't tested everything

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OG and 360 games biggest issue is licensing.

It'll just take longer for Sony to get to the same position + as of now they don't have any auto hdr or other additional software benefits. This doesn't mean that they couldn't add something like this if they wanted

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Sure they can do it in theory, but it's not the same approach Microsoft took. litebrite already posted a quote. I just want to say that nothing the MS tweet says is misleading, because the console in BC has access to all the hardware. No downclocking, no boost mode. Not being able to use architecture advancements is common sense.

Back to your argument "if they wanted", I think companies can do what other companies do in theory, but sometimes there are technical or business reasons why that's not happening. Like PS1-3 BC for example.

Again, referring to the quote posted by litebrite Xbox made sure during Xbox One generation that compatibility won't be a big issue for them and Sony needed to find other ways as they can't time travel and change their PS4 decisions. They made it work eventually.

Each companies have their strengths and thus I just agree in theory that companies can do the same. But the reality is sometimes different. Just compare the online experience between Nintendo, Sony and Microsoft.

 

[Joo]

OG and 360 games biggest issue is licensing.
Sure they can do it in theory, but it's not the same approach Microsoft took. litebrite already posted a quote. I just want to say that nothing the MS tweet says is misleading, because the console in BC has access to all the hardware. No downclocking, no boost mode. Not being able to use architecture advancements is common sense.

Back to your argument "if they wanted", I think companies can do what other companies do in theory, but sometimes there are technical or business reasons why that's not happening. Like PS1-3 BC for example.

Again, referring to the quote posted by litebrite Xbox made sure during Xbox One generation that compatibility won't be a big issue for them and Sony needed to find other ways as they can't time travel and change their PS4 decisions. They made it work eventually.

Each companies have their strengths and thus I just agree in theory that companies can do the same. But the reality is sometimes different. Just compare the online experience between Nintendo, Sony and Microsoft.

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Yeah, thanks for the good info. My point was just that when perf difference between PS5 and XSX is taken into account, there seems to be nothing which decidedly stops Sony from being able to have a PS4 BC with similar performance gains like XB1 games are getting with XSX, and they seem to be working towards it in some ways at least. While there are fundamental differences with past gens, the current gen BC CAN still work in the same way on both machines. It's another thing altogether if it ever will.

Of course the argument wasn't meant as "everything is possible" kinda thing. Sony could sell pancakes if they wanted. It was more in a sense that for Sony there seems to be a perfectly reasonable way to do enhanced BC in terms of technology, time constraints allowing it and the whole process making sense business-wise. At least it would seem like Sony is doing this as PS4 BC games (not all of course) are marketed as having benefits on PS5.

Like litebrite was already good to point out, it seems that it's easier to make XB1 games work well on newer machines like XSX. It still doesn't mean that PS4 games couldn't possibly get to the same level on PS5, as by mimicking GCN architecture, essentially both consoles are handling BC in a similar way in terms of how much power it is possible to utilise. Or am I just wrong to assume this?