Question Speculation: RDNA3 + CDNA2 Architectures Thread

Page 162 - Seeking answers? Join the AnandTech community: where nearly half-a-million members share solutions and discuss the latest tech.

uzzi38

Platinum Member
Oct 16, 2019
2,705
6,427
146

Glo.

Diamond Member
Apr 25, 2015
5,803
4,777
136
That's wrong, because It includes BW from GDDR6.
5300-960 = 4340 GB/s is BW for 96MB infinity cache.
I just don't know If this is the theoretical max or not.
I need to find endnote RX-818

edit: I found It.
View attachment 74955
It looks like It's just max BW of Infinity cache without GDDR6.
So what you wrote is correct for 32MB, but effective BW will depend on actual hitrate.
I mean, the Bandwidth was always separate for IC and for GDDR memory. We knew this since Navi 21/22/23/24.
 

TESKATLIPOKA

Platinum Member
May 1, 2020
2,523
3,038
136
I mean, the Bandwidth was always separate for IC and for GDDR memory. We knew this since Navi 21/22/23/24.
AMD used both for effective bandwidth. 1152 GB/s + 512 GB/s for 1664 GB/s.
xt0wfz1povv51.jpg
 

Glo.

Diamond Member
Apr 25, 2015
5,803
4,777
136
You still don't believe that Strix Point iGPU, if it has 24 CUs and 32 MB IC is a game changer for iGPUs? :)
 
Last edited:

TESKATLIPOKA

Platinum Member
May 1, 2020
2,523
3,038
136
You still don't believe that Strix Point iGPU, if it has 24 CUs and 32 MB IC is a game changer for iGPUs? :)
It's only a rumour, we know how wrong such rumours were about RDNA3 just a month or two before release, Strix Point is still far away.
The rumours about N4 process and being monolithic would make this unrealistic paired with bigger Zen5 cores. Size would be clearly >200mm2.

TDP is also a problem. N4 Phoenix with 12CU boosting to 3GHz has 45W TDP. Game frequency is unknown.
2x bigger IGP at N4 would be impossible unless you significantly reduce clocks.
Even N3(E) with 30-34% reduction in power compared to N5 won't be enough to fit It in 45W If the power draw ratio during gaming is 1:2(15W:30W).
If you can't keep the frequency, then It's kinda pointless to put so much CU in It, 20CU would be a better option.

I still question If 32MB with 55% hitrate is enough in combination with LPDDR5(DDR5). There is no problem with BW of IC.
I would rather have a bigger dynamic SLC(LLC) for both CPU and GPU.
 

insertcarehere

Senior member
Jan 17, 2013
639
607
136
You still don't believe that Strix Point iGPU, if it has 24 CUs and 32 MB IC is a game changer for iGPUs? :)

Given Phoenix is already 180mm^2 on N4 with Zen 4 cores, half the CUs and no infinity cache. Doubling the CUs with Zen 5 + IC would make SP very large on N4 and therefore relatively expensive to produce. Such size needs to be compensated for with a price premium, especially for AMD when they can happily pump out CPU chiplets on such silicon instead.
 

beginner99

Diamond Member
Jun 2, 2009
5,233
1,610
136
You still don't believe that Strix Point iGPU, if it has 24 CUs and 32 MB IC is a game changer for iGPUs? :)

Only because there is basically no reasonable dGPU in the low end. That market was completely abandoned by NV and AMD. Look at the crap the 6500 and 3050 are. 6500 is barely better than a 290x (which I own) and cost on release the same I paid for said 290x about 8 years ago. yeah it's this bad. so easy for anything affordable to shine in that performance bracket.
 
  • Like
Reactions: Tlh97 and coercitiv

IntelUser2000

Elite Member
Oct 14, 2003
8,686
3,786
136
It's only a rumour, we know how wrong such rumours were about RDNA3 just a month or two before release, Strix Point is still far away.

And besides RGT is the same "source" that claimed 2.5x performance of RDNA3 over the predecessor! In reality, sometimes it's half that at 1.25x.

I don't believe in the practicality of big iGPUs because you pretty much lose the big reason you get them in the first place - practically free! And you often don't even get the power advantage either, that's a hit and miss, just toss a coin to decide which.

Actually even current "iGPUs" arguably cost way more than the ones that were bundled with chipsets, back when memory controllers were off die. Because now they bundle it with higher CPUs. You are kinda forced to pay extra if you want the best iGPU.

And it only takes about a single generation before the iGPUs go back down to the bottom of the barrel in terms of dGPUs.
 
Last edited:

TESKATLIPOKA

Platinum Member
May 1, 2020
2,523
3,038
136
Only because there is basically no reasonable dGPU in the low end. That market was completely abandoned by NV and AMD. Look at the crap the 6500 and 3050 are. 6500 is barely better than a 290x (which I own) and cost on release the same I paid for said 290x about 8 years ago. yeah it's this bad. so easy for anything affordable to shine in that performance bracket.
Phoenix with 12CU IGP at 3GHz could be pretty close to even 6500XT, If It wasn't bottlenecked.
It's not that phoenix IGP is so good, but that N24 is too weak because It's too small.
It is only 107mm2 on 6nm, The production cost of that chip is not more than $15. AMD could have made a 24CU, 24MB IC, 96bit GDDR6, which should still be ~150mm2 and cost of die would be only $5 more. With this performance they could have kept MSRP at $199 while still being profitable and everyone would sing odes how great a company AMD is.
But no, AMD had to save a few bucks on cost and we ended up with a pretty bad product.

P.S. RX 6500XT 8GB is a lot better than the 4GB version.
 
  • Like
Reactions: Tlh97 and Kaluan

Kronos1996

Junior Member
Dec 28, 2022
15
17
41
Phoenix with 12CU IGP at 3GHz could be pretty close to even 6500XT, If It wasn't bottlenecked.
It's not that phoenix IGP is so good, but that N24 is too weak because It's too small.
It is only 107mm2 on 6nm, The production cost of that chip is not more than $15. AMD could have made a 24CU, 24MB IC, 96bit GDDR6, which should still be ~150mm2 and cost of die would be only $5 more. With this performance they could have kept MSRP at $199 while still being profitable and everyone would sing odes how great a company AMD is.
But no, AMD had to save a few bucks on cost and we ended up with a pretty bad product.

P.S. RX 6500XT 8GB is a lot better than the 4GB version.

A 150mm2 die makes no sense when they knew they had a 200mm2 Navi 33 coming that blows it away in performance. A stripped down cheap Navi 24 die that can be produced in massive quantities is perfect budget laptop fodder and will be around for years. Their only mistake was releasing it on desktop. 8GB of GDDR6 costs 2-3X more then the silicon, never-mind the PCB/cooler, so that’s not really a major cost factor here.
 

coercitiv

Diamond Member
Jan 24, 2014
6,678
14,278
136
In reality, sometimes it's half that at 1.25x.
They only need to fix the thing to get 2X up and running. I'm surprised you don't know about the thing.

Seriously now, there's some spectacular commitment to performance estimates in this thread, the kind of napkin math I really appreciate. The only problem we have is feeding these wonderful human calculators with "leaked" info that varies from optimistic speculation to pure fabrication. It doesn't matter if folks around here are dedicated, feeding crap at one end results in crap the other end.

If we don't stop echoing "leakers" like RGT and MLID when it has become painfully obvious their signal/noise ratio is poor, threads like this will continue outputting highly distorted estimates when compared with launched products & technologies.
 

TESKATLIPOKA

Platinum Member
May 1, 2020
2,523
3,038
136
And besides RGT is the same "source" that claimed 2.5x performance of RDNA3 over the predecessor! In reality, sometimes it's half that at 1.25x.

I don't believe in the practicality of big iGPUs because you pretty much lose the big reason you get them in the first place - practically free! And you often don't even get the power advantage either, that's a hit and miss, just toss a coin to decide which.

Actually even current "iGPUs" arguably cost way more than the ones that were bundled with chipsets, back when memory controllers were off die. Because now they bundle it with higher CPUs. You are kinda forced to pay extra if you want the best iGPU.

And it only takes about a single generation before the iGPUs go back down to the bottom of the barrel in terms of dGPUs.
Any iGPU in an APU increases the cost, so It's never really free, but It's still pretty useful. Especially when your dGPU dies.:D

I can see a niche market for bigger IGPs, but not for ridiculously big ones.
24CU is still reasonable in my opinion, but It's very questionable If It happens.
TDP will have to increase, but It should still offer better perf/W.
The problem is price as you said.
Production cost would increase only by $20-30, but It will be paired with the fastest CPUs in premium laptops, the cost will be much higher.
Where It could be relatively cheap is desktop. 5600-5700G were sold for a great price.
 
  • Like
Reactions: Tlh97 and Lodix

Kronos1996

Junior Member
Dec 28, 2022
15
17
41
Any iGPU in an APU increases the cost, so It's never really free, but It's still pretty useful. Especially when your dGPU dies.:D

I can see a niche market for bigger IGPs, but not for ridiculously big ones.
24CU is still reasonable in my opinion, but It's very questionable If It happens.
TDP will have to increase, but It should still offer better perf/W.
The problem is price as you said.
Production cost would increase only by $20-30, but It will be paired with the fastest CPUs in premium laptops, the cost will be much higher.
Where It could be relatively cheap is desktop. 5600-5700G were sold for a great price.

If a 24 CU APU exists it’s probably not Strix Point. It’s likely a semi-custom design for some sort of handheld console or a dedicated design to service that market and perhaps thin and light gaming laptops. It wouldn’t make sense from a cost/performance perspective anywhere else. Hell it might just be an Xbox Series S refresh that also goes into Surface Books.
 

TESKATLIPOKA

Platinum Member
May 1, 2020
2,523
3,038
136
A 150mm2 die makes no sense when they knew they had a 200mm2 Navi 33 coming that blows it away in performance.
What are you talking about?
RX 6500Xt was released a year ago, N33 is not released yet.
That 150mm2 chip should have been released at that time instead of 107mm2 Navi 24.
A stripped down cheap Navi 24 die that can be produced in massive quantities is perfect budget laptop fodder and will be around for years.
How did this perfect budget laptop fodder help AMD in laptops?
How many models are available or at least exist?
It's supposedly produced in massive quantities, but It's even more scarce than a 6800U APU laptop.:D
Their only mistake was releasing it on desktop. 8GB of GDDR6 costs 2-3X more then the silicon, never-mind the PCB/cooler, so that’s not really a major cost factor here.
The mistake was even releasing such a small chip.
At least I can buy It a desktop version, even If It's not particularly cheap, but there is no better option.

N24 chip is really cheap to make, you just confirmed It.
That's why I said making a bigger one would make more sense.

What would you rather buy:
107mm2 chip with 4GB/8GB Vram for $199/219
1024SP:64TMU:32ROP:16MB ; game Clock: 2610 MHz ; TDP: 107W
or
150mm2 chip with 6GB/12GB Vram for $239/259
1536SP:96TMU:48ROP:24MB; game Clock: 2491 MHz ; TDP: 120W
The second option would provide better perf/W, perf/$, more Vram and would cost only $40 more.
I think the answer is clear.

edit: 12GB version in clamshell is not the best idea.
 
Last edited:

TESKATLIPOKA

Platinum Member
May 1, 2020
2,523
3,038
136
If a 24 CU APU exists it’s probably not Strix Point. It’s likely a semi-custom design for some sort of handheld console or a dedicated design to service that market and perhaps thin and light gaming laptops. It wouldn’t make sense from a cost/performance perspective anywhere else. Hell it might just be an Xbox Series S refresh that also goes into Surface Books.
If It's a semi-custom design, then that's a problem.
I don't believe It to be for a handheld console. It would consume too much power and handhelds need a good battery life.
There is no OEM who would pay AMD to produce a semi-custom design, maybe Microsoft for Surface, but they don't do gaming laptops.

I think Xbox Series S refresh would be the most likely one If It's a semi-custom design.
Series S has only 20 CUs RDNA2 @ 1.565 GHz, 4.01 TFLOPS
Refresh: 24CU RDNA3 @ 2.6-3 GHz, 8-9.2 TFLOPS (didn't include dual issue ALU)
This actually looks pretty good.
 

Kepler_L2

Senior member
Sep 6, 2020
537
2,199
136
If a 24 CU APU exists it’s probably not Strix Point. It’s likely a semi-custom design for some sort of handheld console or a dedicated design to service that market and perhaps thin and light gaming laptops. It wouldn’t make sense from a cost/performance perspective anywhere else. Hell it might just be an Xbox Series S refresh that also goes into Surface Books.
Or a giant sea monster ;)
 

Kronos1996

Junior Member
Dec 28, 2022
15
17
41
What are you talking about?
RX 6500Xt was released a year ago, N33 is not released yet.
That 150mm2 chip should have been released at that time instead of 107mm2 Navi 24.

How did this perfect budget laptop fodder help AMD in laptops?
How many models are available or at least exist?
It's supposedly produced in massive quantities, but It's even more scarce than a 6800U APU laptop.:D

The mistake was even releasing such a small chip.
At least I can buy It a desktop version, even If It's not particularly cheap, but there is no better option.

N24 chip is really cheap to make, you just confirmed It.
That's why I said making a bigger one would make more sense.

What would you rather buy:
107mm2 chip with 4GB/8GB Vram for $199/219
1024SP:64TMU:32ROP:16MB ; game Clock: 2610 MHz ; TDP: 107W
or
150mm2 chip with 6GB/12GB Vram for $239/259
1536SP:96TMU:48ROP:24MB; game Clock: 2491 MHz ; TDP: 120W
The second option would provide better perf/W, perf/$, more Vram and would cost only $40 more.
I think the answer is clear.
Navi 24 was designed for the same market Nvidia’s MX GPU’s serve. As such, they won’t update it often and designed it to be as cheap as possible so it can be made for the next 3-5 years. Anything bigger would be a waste of silicon for it’s primary purpose as a budget laptop GPU. I don’t think they planned on releasing it to desktop at all initially until the shortages happened and they took advantage.

So why waste all that time and silicon on a 150mm2 die that’ll be in market for one year until Navi 33 arrives? You don’t and that’s why they never made one. Navi 33 will probably be between 6700-6800 XT performance on a 200mm2 6nm die with similar VRAM and component cost as this theoretical 150mm2 chip. They can sell it in $300-400 products which will help offset the big inflation which likely makes sub-$300 GPU’s difficult to profit on. So what makes the most sense for AMD? Exactly what they did.
 

Kaluan

Senior member
Jan 4, 2022
504
1,074
106
Everyone just assumes RDNA3+ (assuming same node) WGPs are the exact same size as Phoenix's RDNA3 WGPs. We don't know that, hell we don't even know how big or small the 6 WGPs or whole IGP is relative to the Phoenix die. Let's wait for proper die shots and measurements first. In any case, it should be way smaller than Rembrandt's.
Maybe it's so small AMD lost the CPU:IGP 1:1 equilibrium they reached with Rembrandt? 😅
 

Glo.

Diamond Member
Apr 25, 2015
5,803
4,777
136
It's only a rumour, we know how wrong such rumours were about RDNA3 just a month or two before release, Strix Point is still far away.
The rumours about N4 process and being monolithic would make this unrealistic paired with bigger Zen5 cores. Size would be clearly >200mm2.

TDP is also a problem. N4 Phoenix with 12CU boosting to 3GHz has 45W TDP. Game frequency is unknown.
2x bigger IGP at N4 would be impossible unless you significantly reduce clocks.
Even N3(E) with 30-34% reduction in power compared to N5 won't be enough to fit It in 45W If the power draw ratio during gaming is 1:2(15W:30W).
If you can't keep the frequency, then It's kinda pointless to put so much CU in It, 20CU would be a better option.

I still question If 32MB with 55% hitrate is enough in combination with LPDDR5(DDR5). There is no problem with BW of IC.
I would rather have a bigger dynamic SLC(LLC) for both CPU and GPU.
It appears Strix Point is on N3 process.

And you may have your wish about SLC fulfilled, after all.
 
  • Love
Reactions: TESKATLIPOKA

TESKATLIPOKA

Platinum Member
May 1, 2020
2,523
3,038
136
I don't mean that there would be both N24 and this chip. I meant this one should have been designed and released as N24.
Navi 24 was designed for the same market Nvidia’s MX GPU’s serve. As such, they won’t update it often and designed it to be as cheap as possible so it can be made for the next 3-5 years. Anything bigger would be a waste of silicon for it’s primary purpose as a budget laptop GPU. I don’t think they planned on releasing it to desktop at all initially until the shortages happened and they took advantage.
N24 was aimed against GA107.
MX models are much weaker, with a single exception being MX570.
GeForce MX570 was announced a month earlier than N24 and has comparable performance to a cutdown N24 is based on GA107.
6500M(Full N24) is comparable to RTX 3050(GA107).
Phoenix should already provide the same level of performance as this cutdown N24 making It rather pointless.
There is absolutely no good reason for N24 to be produced for an additional 3-5 years when even now barely anyone wants them, which is evident by the amount of laptops with It.
So why waste all that time and silicon on a 150mm2 die that’ll be in market for one year until Navi 33 arrives? You don’t and that’s why they never made one. Navi 33 will probably be between 6700-6800 XT performance on a 200mm2 6nm die with similar VRAM and component cost as this theoretical 150mm2 chip. They can sell it in $300-400 products which will help offset the big inflation which likely makes sub-$300 GPU’s difficult to profit on. So what makes the most sense for AMD? Exactly what they did.
Because AMD needs something for <=$249.
That 150mm2 chip wouldn't have worse profits than N24, and It also wouldn't cost much more to make.
It's not like N24 is much cheaper to make than N33, when you compare versions with 8GB Vram, yet price will be very different.
Making a 107mm2 GPU which after a year is made pointless by an IGP from the same company doesn't make much sense to me. :cool: At least my beefed up version of N24 would still be >50% faster than Phoenix and could be sold at least until Strix is out.:)

P.S. I think that 12GB version of mine is too costly to make because of clamshell, I would keep only the 6GB version for $239.
 
Last edited:
  • Like
Reactions: Tlh97

TESKATLIPOKA

Platinum Member
May 1, 2020
2,523
3,038
136
Its still going to be hell of a lot cheaper to design ONE 3 nm product instead of two separate ones.
Isn't the problem actually the amount of APUs they produce?
If they made a lot more, then a second design would be paid for more easily by selling a bigger amount of chips.
I really wonder how many Rembrandt APUs they actually made, because It doesn't look like It was more than a few million chips.
 
Last edited:

Glo.

Diamond Member
Apr 25, 2015
5,803
4,777
136
Isn't the problem actually the amount of APUs they produce?
If they made a lot more, then a second design would be paid for more easily by selling a bigger amount of chips.
I really wonder how many Rembrandt APUs they actually made, because It doesn't look like It was more than a few million chips.
If I were AMD, when Strix Point releases I would just maintain production of ONLY Phoenix, and Strix Point APUs. I don't know how their wafer supply agreements play out with the TSMC, and if they are the reason why AMD has to maintain production of older hardware.