Question Speculation: RDNA2 + CDNA Architectures thread

[uzzi38]

All die sizes are within 5mm^2. The poster here has been right on some things in the past afaik, and to his credit was the first to saying 505mm^2 for Navi21, which other people have backed up. Even still though, take the following with a pich of salt.

Navi21 - 505mm^2

Navi22 - 340mm^2

Navi23 - 240mm^2

Source is the following post: https://www.ptt.cc/bbs/PC_Shopping/M.1588075782.A.C1E.html

 

[amrnuke]

You don't start a price war when you can't supply enough to meet demand to begin with. All you accomplish is lower revenue and lower profit.

And especially not with two companies that have more capital to dig into.

 

[psolord]

So do we know what this 128MB infinity cache is? If I am not mistaken, they said something in the lines of 256bit+infinity cache=Twice the performance of standard 384bit bus. How is this possible? wtf?

Also do the consoles have it? Will it be present on lower tier cards?

 

[psolord]

Official specs.

https://www.amd.com/en/products/specifications/compare/graphics/10516%2C10521%2C10526

Oh wow!

The 6800XT specs are 2X the PS5's!

AMD Playstation 5 GPU Specs

AMD Oberon, 2233 MHz, 2304 Cores, 144 TMUs, 64 ROPs, 16384 MB GDDR6, 1750 MHz, 256 bit

www.techpowerup.com

 

[zinfamous]

So, their charts for direct comparison to RTX are using 6800/6900 with Rage mode and with SAM. Rage mode seems like a silicon lottery deal, and SAM...sounds to me like this generation's "Cool AMD exclusive feature that will be really awesome if the Devs program for it in each specific game" At least, that is in Ian's article, that it requires Dev work for each game, if it is going to provide any benefit.

Man, we've been here before...a lot. Yes, I hope it happens, but I dunno....

Though, if they are able to benchmark it in existing games, I guess that means this is more of a known feature for some time, or something that AMD can already exploit that doesn't require much of anything new?

I wonder if the games where AMD matches or underperforms nVidia with that juice turned out, these are games where these features just don't exist?

Still, at least with the 6800XT, the performance vs 3080 without that stuff looks very decent.

 

[zinfamous]

The 6900XT results are using rage mode and the smart access memory with zen3.

yes, very important to note, because it is a bit of silicon lottery + "benevolence of the devs" to hope that the feature (SAM) is active.

I also want to see if SAM will work with AM4 4xx boards + Zen3 after 2021 firmware update. ...and if all 4xx boards are created equal for Zen3 compatibility.

lots of ***'s to sift through in those posted performance numbers.

 

[Glo.]

So, their charts for direct comparison to RTX are using 6800/6900 with Rage mode and with SAM. Rage mode seems like a silicon lottery deal, and SAM...sounds to me like this generation's "Cool AMD exclusive feature that will be really awesome if the Devs program for it in each specific game" At least, that is in Ian's article, that it requires Dev work for each game, if it is going to provide any benefit.

Man, we've been here before...a lot. Yes, I hope it happens, but I dunno....

Though, if they are able to benchmark it in existing games, I guess that means this is more of a known feature for some time, or something that AMD can already exploit that doesn't require much of anything new?

I wonder if the games where AMD matches or underperforms nVidia with that juice turned out, these are games where these features just don't exist?

Still, at least with the 6800XT, the performance vs 3080 without that stuff looks very decent.

For the second time, read again the slides of testing methodology about RX 6800XT. Rage Mode is only for RX 6900XT.

Secondly. You accuse AMD of overplaying their GPUs, when AMD is showing absolute worst case scenario, since the AIB GPU will clock way higher than reference designs.

 

[Glo.]

https://twitter.com/x/status/1321508119797780480

I don't think there is anything to add to this.

O_O

 

[Saylick]

Hmm, there's some more info about the Infinity Cache on AMD's RDNA 2 webpage in the footnotes:

1. Measurement calculated by AMD engineering, on a Radeon RX 6000 series card with 128 MB AMD Infinity Cache and 256-bit GDDR6. Measuring 4k gaming average AMD Infinity Cache hit rates of 58% across top gaming titles, multiplied by theoretical peak bandwidth from the 16 64B AMD Infinity Fabric channels connecting the Cache to the Graphics Engine at boost frequency of up to 1.94 GHz. RX-535

This is in reference to AMD's claim of the following:
- 256-bit 16 Gpbs GDDR6 = 512 GB/s
- 384-bit 19.5 Gpbs GDDR6x = 936 GB/s
- 256-bit 16 Gpbs GDDR6 + 128MB Infinity Cache = 1664 GB/s Effective

A shot directly across the bow of Ampere.

 

[Hitman928]

SAM...sounds to me like this generation's "Cool AMD exclusive feature that will be really awesome if the Devs program for it in each specific game" At least, that is in Ian's article, that it requires Dev work for each game, if it is going to provide any benefit.

I don't think it requires developers to program for it, I found that highly doubtful given they showed it's effects across 10 existing games that I highly doubt they patched for this feature. I think it's more that SAM's performance improvement will be highly variable from game to game and could be coded for to get max benefit. AMD didn't go into hardly any detail about the feature so we'll have to wait and see exactly how it works though.

 

[AnandThenMan]

Is Rage Mode named after Jensen right now?

 

[Saylick]

Is Rage Mode named after Jensen right now?

The more JHH gets pissed, the faster Big Navi gets!

 

[moinmoin]

SAM...sounds to me like this generation's "Cool AMD exclusive feature that will be really awesome if the Devs program for it in each specific game"

You mean SAM is to AMD as DLSS is to Nvidia?

 

[Hail The Brain Slug]

yes, very important to note, because it is a bit of silicon lottery + "benevolence of the devs" to hope that the feature (SAM) is active.

I also want to see if SAM will work with AM4 4xx boards + Zen3 after 2021 firmware update. ...and if all 4xx boards are created equal for Zen3 compatibility.

lots of ***'s to sift through in those posted performance numbers.

Gamers Nexus reporting Rage Mode is not an overclock. It's just a mild power limit increase, which in turn allows for a slightly increased boost clock in games.

No lottery for this. I assume it's because they didn't want to release a card with >300W power limit.

Gamers Nexus also stating AMD has said Rage Mode only accounts for a 1-2% performance increase. AMD also claims smart memory access works automatically and the performance gains they have shown are simply from it being enabled, not because the games have support for it baked in.

 

[Antey]

Could this 'infinity cache' be applied to future RDNA2 iGPUs? something like intel iris graphics l4 cache? bw solution for iGPU perhaps??

 

[MrTeal]

It will be very interesting to see benchmarks of the 6800XT with a 3800X vs a 5800X to see what the actual performance increase of SAM is.

 

[GodisanAtheist]

Wow wow wow what a great showing by AMD! Glad we were able to keep the hype under control folks

In terms of preliminary benchmarks (naturally, wait for reviews) they exceeded my expectations by a longshot. They even pulled some of the presentation tricks that we were discussion here as well (and one more thing...)

A couple points:

- Prices. Competitive for what they're offering vs the competition, but still too rich for my blood. They know they're going to sell everything they make.

- The fact that they're going to offer a 60 CU N21 at all also strongly suggests they are severely supply constrained at the moment and are harvesting even garbage dies to sell. Its weird because what happens when supply opens up? AMD isn't going to be lopping off 20CUs off a die to sell forever, are they?

-No RT benchmarks. Sounds like they don't have a good partner to show off their RT tech on PC at the moment (everything out there is RTX right now) so they just glossed over it. We know its there and it works (rather well) thanks to some XSX and PS5 game reveals.

More thoughts soon...

 

[Campy]

It will be very interesting to see benchmarks of the 6800XT with a 3800X vs a 5800X to see what the actual performance increase of SAM is.

I think they mentioned there would be a BIOS option to toggle it? Also that it was a 500 series mobo feature.

 

[CastleBravo]

It will be very interesting to see benchmarks of the 6800XT with a 3800X vs a 5800X to see what the actual performance increase of SAM is.

Will also be interesting to see 6800 XT vs 3080 on an non-Zen3 CPU. The value of the 6800 XT might not look as good if you have to spend another $300+ on a CPU and maybe even a motherboard for it to match/beat the 3080.

 

[Saylick]

Looks like there's another video from AMD. My apologies if this has been posted already.

Some explanation on AMD Smart Access Memory, Anti-Lag, Radeon Boost, etc.

 

[dacostafilipe]

SAM...sounds to me like this generation's "Cool AMD exclusive feature that will be really awesome if the Devs program for it in each specific game" At least, that is in Ian's article, that it requires Dev work for each game, if it is going to provide any benefit.

Linus talks about a PCIe protocol limitation (Base Address Registers size), so not game specific, but certainly devs could optimise for it.

 

[exquisitechar]

- The fact that they're going to offer a 60 CU N21 at all also strongly suggests they are severely supply constrained at the moment and are harvesting even garbage dies to sell. Its weird because what happens when supply opens up? AMD isn't going to be lopping off 20CUs off a die to sell forever, are they?

I don't think they intend to sell many 6800s, the main one is the XT. 6700XT will probably be much more attractive, IMO, but it isn't ready.

-No RT benchmarks. Sounds like they don't have a good partner to show off their RT tech on PC at the moment (everything out there is RTX right now) so they just glossed over it. We know its there and it works (rather well) thanks to some XSX and PS5 game reveals.

Yeah, I think AMD will shine in DXR 1.1 titles. Performance will be inferior to Ampere's in DXR 1.0 titles.

 

[HurleyBird]

Could this 'infinity cache' be applied to future RDNA2 iGPUs? something like intel iris graphics l4 cache? bw solution for iGPU perhaps??

I'm doubtful for anything other than a very small cache given that the APUs are optimized for small die sizes, unless perhaps the L3 can be shared with CPU cores. I imagine that's the eventual plan, although I don't know if that's in the cards for the first RDNA2 APU configurations.

 

[moinmoin]

Could this 'infinity cache' be applied to future RDNA2 iGPUs? something like intel iris graphics l4 cache? bw solution for iGPU perhaps??

AMD likened Infinity Cache to L3 cache in CPUs. I'd expect a RDNA2 based APU to share its L3 cache between CPU and GPU.

It will be very interesting to see benchmarks of the 6800XT with a 3800X vs a 5800X to see what the actual performance increase of SAM is.

AMD has been pretty opaque on that point, but I expect the requirement for Ryzen 5000 and 500 series boards to boil down to PCIe 4 being a requirement for SAM. The comparison with Ryzen 3000 will be interesting indeed.

 

[Geranium]

Looks like 128MB Infinity Cache is true afterall and looks like you dont need to specially program for it.
Also this 'big Navi' has 128 ROP not 64 as rumor suggested.
Hopefully those cards will not have the fate of R9 290X.

Another note: Why no 720p benchmark AMD?? That is the most popular resolution that most people use.

 

[Avalon]

You're doing it wrong.

Realize how close the 6800 is to 6800xt is price wise, realize how much sweeter that extra performance is and justify spending not $499 but $649!

Lol, fair, but I'm not sure I want to drop that amount of moolah.