Discussion RDNA4 + CDNA3 Architectures Thread

DisEnchantment · Mar 23, 2022

With the GFX940 patches in full swing since first week of March, it is looking like MI300 is not far in the distant future!
Usually AMD takes around 3Qs to get the support in LLVM and amdgpu. Lately, since RDNA2 the window they push to add support for new devices is much reduced to prevent leaks.
But looking at the flurry of code in LLVM, it is a lot of commits. Maybe because US Govt is starting to prepare the SW environment for El Capitan (Maybe to avoid slow bring up situation like Frontier for example)

See here for the GFX940 specific commits

History for llvm/lib/Target/AMDGPU - llvm/llvm-project

The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. - History for llvm/lib/Target/AMDGPU - llvm/llvm-project

github.com

Or Phoronix

More AMD "GFX940" Enablement Work Landing In LLVM - Phoronix

www.phoronix.com

There is a lot more if you know whom to follow in LLVM review chains (before getting merged to github), but I am not going to link AMD employees.

I am starting to think MI300 will launch around the same time like Hopper probably only a couple of months later!
Although I believe Hopper had problems not having a host CPU capable of doing PCIe 5 in the very near future therefore it might have gotten pushed back a bit until SPR and Genoa arrives later in 2022.
If PVC slips again I believe MI300 could launch before it

This is nuts, MI100/200/300 cadence is impressive.

Previous thread on CDNA2 and RDNA3 here

Question - Speculation: RDNA3 + CDNA2 Architectures Thread

Man I have been dying to make this one for a while now. First rumours for RDNA3 are here so new thread time! Just going to start off with this one for now: kopite7kimi on Twitter: "@VideoCardz Ah, I mean a simple mcm design with 10240 cores is not enough. Because the lift from RDNA2 to RDNA3...

forums.anandtech.com

SolidQ · Apr 7, 2024

TESKATLIPOKA said:
I am certain you already saw It, but All The Watts!! pretty much confirmed that what you thought is frequency in that tweet is something else.

on page72 picture from twitter

Abwx · Apr 7, 2024

TESKATLIPOKA said:
N48 >3GHz and not 2770
I am certain you already saw It, but All The Watts!! pretty much confirmed that what you thought is frequency in that tweet is something else.
I think It's IC BW, but I could be wrong.

He started in a first post by stating 2770 and then in a later post he said 3GHz.

At first he aligned the datas stating 32 WGP/64 CUs/256b bus/693GB/s /2770MHz/ 240mm2.

It cant be more clear than this, 2770GB/s as you stated would imply chips with roughly 100Gb/s speed while a 7800XT FI use 20Gb/s speed chips, you can see the huge discrepancy.

Abwx · Apr 7, 2024

SolidQ said:
it's forest heavy scene. That how is marketing working on people. Show AW2 and CP2077 and people will say "nice NV much faster in RT", and they think it's for every game same situation.

They could have found a scene where the 7900XTX tank as much but with the 4070ti tanking more than this forest scene, guess that they ll try to find the "good" scene where the 4070ti doesnt tank too much even if there s scene where its FPS are lower than in this one, but as you say marketing is not about accuracy and honnesty.

Timorous · Apr 7, 2024

Abwx said:
He started in a first post by stating 2770 and then in a later post he said 3GHz.

At first he aligned the datas stating 32 WGP/64 CUs/256b bus/693GB/s /2770MHz/ 240mm2.

It cant be more clear than this, 2770GB/s as you stated would imply chips with roughly 100Gb/s speed while a 7800XT FI use 20Gb/s speed chips, you can see the huge discrepancy.

This is the blurb from the 7800XT spec page over at AMD

GPU Memory
AMD Infinity Cache Technology
64 MB
Memory Speed
Up to 19.5 Gbps
Max Memory Size
16 GB
Memory Type
GDDR6
Memory Interface
256-bit
Memory Bandwidth
Up to 624 GB/s
Effective Memory Bandwidth
Up to 2708 GB/s

And this is for the 7600xt

GPU Memory
AMD Infinity Cache Technology
32 MB
Memory Speed
Up to 18 Gbps
Max Memory Size
16 GB
Memory Type
GDDR6
Memory Interface
128-bit
Memory Bandwidth
Up to 288 GB/s
Effective Memory Bandwidth
Up to 477 GB/s

2770 and 515 are both effective bandwidths for N48 and N44 respectively.

SolidQ · Apr 7, 2024

Abwx said:
ll try to find the "good" scene where the 4070ti doesnt tank too much even if there s scene where its FPS are lower than in this one, but as you say marketing is not about accuracy and honnesty.

We can understand it, but typical users don't understand it. Just looking on AW2/CP2077 numbers and buyed NV.
This situation is boring, because always force show CP2077, like it's only this game on planet and you playing it 24\7

About RDNA4 it's interesting will be there cutdown N48(7800XT perf) and N44(6700-6700XT perf)

Abwx · Apr 7, 2024

Timorous said:
This is the blurb from the 7800XT spec page over at AMD

GPU Memory
AMD Infinity Cache Technology
64 MB
Memory Speed
Up to 19.5 Gbps
Max Memory Size
16 GB
Memory Type
GDDR6
Memory Interface
256-bit
Memory Bandwidth
Up to 624 GB/s
Effective Memory Bandwidth
Up to 2708 GB/s

And this is for the 7600xt

GPU Memory
AMD Infinity Cache Technology
32 MB
Memory Speed
Up to 18 Gbps
Max Memory Size
16 GB
Memory Type
GDDR6
Memory Interface
128-bit
Memory Bandwidth
Up to 288 GB/s
Effective Memory Bandwidth
Up to 477 GB/s

Timorous said:
2770 and 515 are both effective bandwidths for N48 and N44 respectively.

That s quite possible after all, we ll see once final specs are published.

SolidQ said:
We can understand it, but typical users don't understand it. Just looking on AW2/CP2077 numbers and buyed NV.
This situation is boring, because always force show CP2077, like it's only this game on planet and you playing it 24\7

About RDNA4 it's interesting will be there cutdown N48(7800XT perf) and N44(6700-6700XT perf)

If the leaked specs are accurate then it should be very competitive, dunno for RT but that wont be a game changer for the time to come, perfs losses are just to big and most of the time this bring nothing to the image quality, but you re right that it s used as a marketing gimmick that can work.

eek2121 · Apr 7, 2024

Ghostsonplanets said:
https://twitter.com/x/status/1776266835002077590

The Navi 4 follows the Navi 3 by removing the older design to improve density.

Navi 44 should be rough in-line with 4060 Ti/Radeon 6750XT according to rumors iirc. Maybe even the 7700XT.

130mm² size might be in part due to N4P manufacturing node, but it's still very impressive. We need to remember that this is a monolithic die with a huge amount of cache onboard, which doesn't shrink much from N6 -> N5. That AMD still was able to get such level of reduction in are is quite impressive imo.

I really wonder how AMD will price N44. 130mm² is so small that they would be able to release a very cheap part. Maybe the return of $199 budget GPUs? Would be amazing.

CouncilorIrissa said:
N44 still only has 2/3 of 7700XT's memory bandwidth, so little chance of competing against the 7700XT (unless it's somehow massively less membw hungry)

lol no.

AMD's best next gen will beat NVIDIA's best this gen. RNDA4 provides a solid uplift. Looking forward to the release.

EDIT: Also, no, you can't compare memory bandwidth numbers cross-gen due to architectural differences, and RDNA3 wasn't bandwidth limited anyway. RNDA4 won't be a miracle, but it will be better than RDNA3 in every way. There is a reason they elected not to go bigger, and it wasn't just $$$.

jpiniero · Apr 7, 2024

eek2121 said:
EDIT: Also, no, you can't compare memory bandwidth numbers cross-gen due to architectural differences, and RDNA3 wasn't bandwidth limited anyway. RNDA4 won't be a miracle, but it will be better than RDNA3 in every way. There is a reason they elected not to go bigger, and it wasn't just $$$.

The 7900GRE def seems very bandwidth limited.

Saylick · Apr 7, 2024

jpiniero said:
The 7900GRE def seems very bandwidth limited.

I've heard that a simple memory OC brings 10%, maybe even up to 15%, higher performance to the 7900 GRE. If that doesn't suggest a bandwidth bottleneck, Idk what does.

Mahboi · Apr 7, 2024

eek2121 said:
RNDA4 won't be a miracle, but it will be better than RDNA3 in every way. There is a reason they elected not to go bigger, and it wasn't just $$$.

That's an odd description. What reason is there to not go bigger if your uarch is solid?

Saylick · Apr 7, 2024

eek2121 said:
lol no.

AMD's best next gen will beat NVIDIA's best this gen. RNDA4 provides a solid uplift. Looking forward to the release.

EDIT: Also, no, you can't compare memory bandwidth numbers cross-gen due to architectural differences, and RDNA3 wasn't bandwidth limited anyway. RNDA4 won't be a miracle, but it will be better than RDNA3 in every way. There is a reason they elected not to go bigger, and it wasn't just $$$.

I find it hard to believe that N44 will beat a RTX 4090, unless I misunderstood what you meant. Did you mean that a hypothetical big RDNA 4 will beat AD102?

SolidQ · Apr 7, 2024

Saylick said:
I find it hard to believe that N44 will beat a RTX 4090

I'd Assuming he's talking about RDNA5 top, which should be RDNA4 or it's about N48, which i can't believe it's beat 4090.
P.S maybe there is super secret N42.

eek2121 · Apr 7, 2024

Mahboi said:
That's an odd description. What reason is there to not go bigger if your uarch is solid?

Time vs. Money.

Saylick said:
I find it hard to believe that N44 will beat a RTX 4090, unless I misunderstood what you meant. Did you mean that a hypothetical big RDNA 4 will beat AD102?

Yes, AMD's best will beat a 4090.

igor_kavinski · Apr 7, 2024

eek2121 said:
Yes, AMD's best will beat a 4090.

Jensen won't let that happen. So 4090 Ti incoming?

Mahboi · Apr 7, 2024

eek2121 said:
Time vs. Money.

Now it's even more cryptic.
I'm gonna interpret that as "get less products out for RDNA 4 and push all the personnel onto RDNA 5 as early as possible" then.

SolidQ · Apr 7, 2024

igor_kavinski said:
Jensen won't let that happen. So 4090 Ti incoming?

5090 is coming. There is no question RDNA5 will beat 4090, but problem is 5090

Kepler_L2 · Apr 7, 2024

eek2121 said:
Yes, AMD's best will beat a 4090.

Nope

eek2121 · Apr 7, 2024

Kepler_L2 said:
Nope

Me vs. Kepler, I'm gonna let this comment stand and double down. This will be fun. 😍

SolidQ · Apr 7, 2024

eek2121 said:
Me vs. Kepler, I'm gonna let this comment stand and double down. This will be fun

Ok we're waiting

branch_suggestion · Apr 7, 2024

SolidQ said:
5090 is coming. There is no question RDNA5 will beat 4090, but problem is 5090

Oh boy...

Ghostsonplanets · Apr 7, 2024

I mean, if we go by the leaks, N48 is >7900 GRE but < 7900 XTX. And the XTX is behind 4090, thus its to be expected that N48 won't beat 4090.

It's clear, however, that AMD is gearing up for RDNA 5 to have a competitive stack, from bottom to Halo.

Mahboi · Apr 7, 2024

Ghostsonplanets said:
It's clear, however, that AMD is gearing up for RDNA 5 to have a competitive stack, from bottom to Halo.

For now.
After RDNA 3 decided to jump into the well and RDNA 4 decided to cut off its own head, I'll politely wait and get confirmation that RDNA 5 doesn't also get a "oopsie, in the end we canceled the high end" before I talk about any performance expectations.
I'm getting quite tired of promises that don't come to fruition.

GodisanAtheist · Apr 7, 2024

Mahboi · Apr 7, 2024

Mahboi · Apr 7, 2024

Ghostsonplanets said:
It's clear, however, that AMD is gearing up for RDNA 5 to have a competitive stack, from bottom to Halo.

I'm not worried about gearing up. I'm worried that the absolute lack of interest from AMD means that in 1.5 years, we get Zen 6, we get MI450X, and we get a very polite "btw that's where all the wafers are going, so we got some smol & cute GPUs for a high price for you".
Reminder that Blackwell decided that taking FP64 and backbreaking it to give more attention to FP4 was the right call.
I wouldn't be surprised if more things get dumpstered for the Mariachi Hype.

Discussion RDNA4 + CDNA3 Architectures Thread

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