Digital Foundry Article Technical Discussion [2021]

I think you are right, looking at how xss performs i doubt its cuted down BC mode. If it was cuted down BC mode i dont see why XSS couldn't run at 4k60fps as well. Performance issues on ps5 are probably due to some weird software issues, afterall game is using old UE3+

 

Every BC title released after July 13 required the title to run BC on PS5 in native mode.
https://www.eurogamer.net/articles/...tation-5-compatible-from-july-sony-tells-devs

Games before July 13 were not forced to comply with PS5 native mode so they can run in Pro Legacy and PS4 legacy, but most were tested to run at PS5 native anyway. The goal of releasing a game at PS5 native mode is to ensure its running maximum clocks without crashing, otherwise there are 2 locked preset ones below in case a PS5 mode induced crashing.

Judging by the resolution differences and framerate differences, I think it’s fair to say that PS5 is using boosted clocks and PS5 BC native mode here. I don’t see any evidence that this is running in Pro Legacy or PS4 Legacy mode.

PS5 doesn’t limit CUs for BC. So the only way I see it gaining that extra performance is to be running native mode.

About my only explanations I can have here for its performance is that BC native mode still runs on variable clock speeds based upon a chosen rule set. It may be in PS5 interests at times to slow down the clock rate during BC mode in moments in thinks it could crash the game.

But that’s about the best I’ve got. Poor coding otherwise. Unfortunately for the dips etc and lack of Higher AF. Maybe worthwhile working out the math for GCN flops because GCN can only issue a new instruction every 4 cycles as opposed to every cycle on RDNA. This may also have an affect here

 

In BC mode the information about available game and clocks are given by the PS5 firmware. For instance at launch P.T. was compatible with PS5 but it wasn't compatible anymore after a PS5 update.

The compatible PS5 mode (on the PS4 game) is implemented in the game code and means the game must perfectly "work" on PS5 and formally recognize the PS5 hardware. But the developer can't decide the GPU clocks on their PS4 game. As written in the EG article, it is done by Sony.

By the way technically devs also can't know in advance the GPU clocks running on their retail PS5 games.

PS4 games (like this one) have this warning on the store because the compatibility is managed by the PS5 OS and not by the game itself:

 

Yea, I don't think that's been in question here. I mean, for the sake of argument, it's taken for granted here that we assume there is no particular load that will cause PS5 to dip much below its maximum clockspeeds (and that is controlled by the OS), so in that sense it's okay for people to assume to treat that method the same here, since the OS is in control of the clockspeeds for native PS5 BC mode. The reality is somewhere in there, but I dunno where. There hasn't been any indication to me that PS5 BC modes by the OS will aggressively downclock, otherwise I have a hard time believing it's going toe to toe on this title 4K60 with XSX without it.

So TLDR; I think it's reasonable to be on the side to assume the clocks are fairly boosted.

 

Not to say it wasn't work but it doesn't seem have been much of an issue for them. They've essentially relit the whole game in a relatively short development window thanks to the fast iteration times. The game doesn't look more bland for it's more realistic lighting tech.

 

No, that mode only does not allow instructions other than GCN had. IPC should still remain the same as IPC depends from multiple factores (e.g. cache-speed, register speed & size, ...). I guess this is not a hardware-feature, it should only be on softare/API side. The API just doesn't use the new functions, .... RDNA is perfectly capable of executing everything GCN could. Some commands might j

I would also add, just like the strange performance drop in Need for speed hot pursuit (remaster) on xbox it is just a strange "bug". Overall the performance is ok with minor drops here and there and a big drop in that one scene. Didn't DF also mention some dynamic resolution scaling?
I guess they patch these minor drops out in the next few weeks and maybe even the big drop.

 

I missed that, how long was this version of the game in development?

 

Don't hammer me if wrong, but I recall a roadmap that Exodus would get the full next-gen treatment around November when consoles released.
February they announced the enhanced edition.
PC edition is already out? Or is out tomorrow or someting, I don't recall.
Consoles are due in June. So a little over 7 months to develop and re-light everything and performance optimization.

edit: https://www.4a-games.com.mt/4a-dna/...-for-playstation-5-and-xbox-series-xs-upgrade

 

Is it fully native though? I seem to recall there being a few different profiles. One of which was a straightforward doubling of the PS4Pro's. So although all games after July have to be validated for the PS5 too, they don't necessarily clock at a variable 2.23 GHz.

I'll see if I can find a reference. I may have just plucked this from a very boring dream.

 

Its native BC, not native to PS5.
Native BC implies it' runs on PS5 boost rates. Not that it's leveraging the IPC of RDNA2.

Frankly, I suspect both of these consoles are likely running the slower APIs, so DX11 and GNM+ respectively given the age of the engines in question (I doubt they converted to a low level API). So performance output is dismal compared to say a 3060 or something that eats DX11 titles.

 

Regardless of how you slice it, Sony should be working on improving PS5 BC experience. No one can't deny Microsoft is providing a better experience in this area.

 

no, in best case scenario it can run full boost with increased ipc, but its more complicated as for example there are graphic glitches in some games (even in Mass Effect remaster) or rare odd drops like ac unity in 1080p and here in ME.

 

It's what you and I would like, but there's the question of whether it's a business priority, if it's even possible to do what Xbox is doing now on a technical level with the PS4/5's framework. Sony will very likely sell every PS5 it can make through the next 2 years - over that time there will be more remasters, some full remakes, along with full-fledged sequels to the PS4's most popular titles.

It's very cool what Xbox is doing and as I play a lot of old games I love the attention being paid to it, but while Sony can't come close to satisfying demand until quite a ways from now I just don't see this deficiency being any threat to their bottom line. The longer this generation goes the less these enhancements matter for potential new buyers I think.

 

I am not sure exactly what it is I said that is bs but ok. Both consoles run at full speed in BC mode that these games that are not native PS5 or XSX games. They have access to the full hardware, they just don't have access to the advanced suite of features so, in essence, they run as 10.28 and 12.15 tflops gcn in this mode.

 

Yes there has being. Almost all old Ubisoft PS4 games like AC Unity, Syndicate or Division 2. The first who hypothetized the PS5 could run some PS4 games at PS4 GPU clocks was actually DF (John) in an article about that game running on XSX and PS5 when he noticed the game was having big framedrops in GPU limited areas (and was locked 60fps in CPU limited areas).

This is managed by the PS5 firmware, not the dynamic clock system.

 

So around six months? That's not an insignificant amount of time.

 

you can't say it use full ps5 power and later but its only gcn compatible and we don't know if full clocks are used all the time as ps5 has few compatible modes (not to mention loading speeds in cb mode and some other rare prolems), its either full ps5 power or not

 

to develop the RT, performance optimization and redo the lighting? Fairly reasonable considering they likely are working on other projects. You still need about a month to test and publish, 4 platforms, 2 GPU types that handle RT differently, make sure things aren't broken, Q&A, all of this accomplished during the COVID era as well. All things considered, I think respectably it's a very fast turn around. I don't think many other companies would succeed as quickly as this.

This is a very well run studio. Honestly I'm really impressed.

 

The aforementioned titles were all released before July 13 2020. Any title released after July 13th must run PS5 BC Native, meaning it has to support the boost clocks that are determined by the OS that should not apply to a title that is released 10 months after that deadline. And for obvious reasons, it's pretty clear running 4Pro clocks is incapable of hitting 4K60.

You don't recall this awesome slide that spawned a lot of threads?

 

Honestly, I thought this was clear to everybody by now.