Question Speculation: RDNA3 + CDNA2 Architectures Thread

[uzzi38]

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 is much bigger than from RDNA1 to RDNA2. We should expect many big improvements in GFX11. 🤔" / Twitter

 

[Timorous]

AMD unveils Radeon Pro W7900 48GB and Pro W7800 32GB RDNA3 workstation GPUs - VideoCardz.com

AMD Radeon Pro W7900 & W7800 announced The company confirms specs and pricing of Radeon PRO GPUs with RDNA3 architecture. AMD Radeon Pro W7900 features 96 Compute Units (full Navi 31) combined with 48GB of GDDR6 ECC memory. This is a flagship workstation solution based on the same GPU as the...

videocardz.com

AMD releasing RDNA3 Radeon Pros. The W7900 is basically a 7900 XTX with 48 GB of memory; the W7800 is a new spec that has 70 CUs and 256 bit so 32 GB of memory. Possibly comparable to a theoretical 7900 non-XT.

70CUs would indicate 5 Shader engines enabled with 14CUs per shader engine instead of the full 6 SE + 16CUs per SE of the top model. That is quite a cut down part.

So I presume the spec would be as follows if this cut was also used as a GPU (possibly 7800XT IMO)

64MB L3
16GB GDDR6
70 CUs
70 RTcores
160 ROPs
280 TMUs.
640 GB/s bandwidth if 20 Gbps ram is used

Give it a 2.5-2.6ghz boost clock and it should perform a bit ahead of the 6950XT. Possible it gets released as a 7800XT but I expect AMD would much rather make N32 work as the 7800XT by increasing clocks to 3Ghz as they would be similar in performance and the N32 part would cost less to make.

 

[leoneazzurro]

The W7900 has the full spec N31 with MORE RAM AND higher nominal clock AND lower TBP AND higher specs on DP 2.1.
Highly binned part or new stepping?

EDIT: clock refers to boost, so it's the same as the 7900XTX. So likely to be highly binned parts with pro features enabled.

 

[deasd]

RX7600 exist. Now I just wonder the spec especially vram size.

https://twitter.com/x/status/1646447390847815681

 

[Mopetar]

Probably 8 GB. Otherwise there have been a lot of leaks regarding Navi 33 specs so the only thing that we really don't know is where the clock speed will end up. I suppose the price is also unknown.

 

[Heartbreaker]

Probably 8 GB. Otherwise there have been a lot of leaks regarding Navi 33 specs so the only thing that we really don't know is where the clock speed will end up. I suppose the price is also unknown.

Yeah, 128 bit bus, the same as NVidia 4060/4060 Ti, really limits them both to 8GB of RAM without making things more complicated.

 

[PJVol]

AMD releasing RDNA3 Radeon Pros. The W7900 is basically a 7900 XTX with 48 GB of memory; the W7800 is a new spec that has 70 CUs and 256 bit so 32 GB of memory. Possibly comparable to a theoretical 7900 non-XT.

Well, that's probably how consumer parts should have been called, 'cause giving the 84CU part 7900XT name seems to me beyond logic.

the only thing that we really don't know is where the clock speed will end up. I suppose the price is also unknown.

Yeah, just a couple of minor details )
Now it remains to find out whether N32 gpu also exists (whatever it's called), preferably not in the form of a logo

 

[jpiniero]

Well, that's probably how consumer parts should have been called, 'cause giving the 84CU part 7900XT name seems to me beyond logic.

It should be obvious - they wanted room for a second cut N31 which would be called the RX 7900.

The amount of GCDs that don't meet the 7900 XT's specs is likely to be very low so a second cut doesn't really make sense unless they were going to pull an nVidia and basically discontinue the 7900 XT for a model which has less MCDs and memory for the current 7900 XT's price.

 

[Timorous]

Yeah, 128 bit bus, the same as NVidia 4060/4060 Ti, really limits them both to 8GB of RAM without making things more complicated.

128bit can handle 16GB okay.

AMD could make 7600 8GB and 7600XT 16GB or they could allow AIBs to offer a 16GB variant. Depends on the price point AMD want to hit. $300 or less and 8GB is fine, more than that and I think they need 16GB (well really 12GB would have been fine but that does not work cleanly with a 128 bit bus).

 

[Ajay]

128bit can handle 16GB okay.

AMD could make 7600 8GB and 7600XT 16GB or they could allow AIBs to offer a 16GB variant. Depends on the price point AMD want to hit. $300 or less and 8GB is fine, more than that and I think they need 16GB (well really 12GB would have been fine but that does not work cleanly with a 128 bit bus).

Yeah, they'll be using GDDR6 (not X) to keep the cost down anyway.

 

[Heartbreaker]

128bit can handle 16GB okay.

128 bits is only 4, 32 bit channels. Max size GDDR chips are 2GB on a 32 bit data bus.

2GB x4 = 8GB.

So 8GB is the maximum VRAM with one GDDR chip/channel.

They could do 2 chips/channel, but that's the complication I mentioned. It's a more expensive/complicated board design. So I really doubt they will do this on the lower end Navi 33 cards.

Navi 32 will have 256 bit, 16GB of RAM, and likely a cut down 192 bit, 12GB lower end cut.

Navi 33 with 128 bit would then logically be 8GB.

 

[blckgrffn]

128 bits is only 4, 32 bit channels. Max size GDDR chips are 2GB on a 32 bit data bus.

2GB x4 = 8GB.

So 8GB is the maximum VRAM with one GDDR chip/channel.

They could do 2 chips/channel, but that's the complication I mentioned. It's a more expensive/complicated board design. So I really doubt they will do this on the lower end Navi 33 cards.

Navi 32 will have 256 bit, 16GB of RAM, and likely a cut down 192 bit, 12GB lower end cut.

Navi 33 with 128 bit would then logically be 8GB.

Is that how the difficult-to-find 8GB 6500xt was able to exist?

It does seem like ram and flash prices have been in a relative free fall, I wonder if that will matter.

 

[jpiniero]

Is that how the difficult-to-find 8GB 6500xt was able to exist?

Yes and the Pro products.

 

[Heartbreaker]

Is that how the difficult-to-find 8GB 6500xt was able to exist?

It does seem like ram and flash prices have been in a relative free fall, I wonder if that will matter.

I'm surprised the did this for a consumer card, unless they repurposed the pro board.

The only tear down images I have seen for 6500 were for the 4GB model. It had 2 VRAM chips and no pads for any more chips front or back.

 

[blckgrffn]

I'm surprised the did this for a consumer card, unless they repurposed the pro board.

The only tear down images I have seen for 6500 were for the 4GB model. It had 2 VRAM chips and no pads for any more chips front or back.

PULSE AMD Radeon™ RX 6500 XT 8GB

<p>Up to 2855 MHz, 8GB/64 bit DDR6. 18 Gbps Effective</p>

www.sapphiretech.com

¯\_(ツ)_/¯

I didn't chase it down to see if I could ever buy it.

Radeon RX 6500 XT 8GB Only Costs $20 More Than 4GB Version

Double the VRAM for 10% more

www.tomshardware.com

 

[DeathReborn]

PULSE AMD Radeon™ RX 6500 XT 8GB

<p>Up to 2855 MHz, 8GB/64 bit DDR6. 18 Gbps Effective</p>

www.sapphiretech.com

¯\_(ツ)_/¯

I didn't chase it down to see if I could ever buy it.

Radeon RX 6500 XT 8GB Only Costs $20 More Than 4GB Version

Double the VRAM for 10% more

www.tomshardware.com

The 8GB Sapphire 6500XT was available in the UK at only 1 retailer that I know of but is OOS now.

 

[Heartbreaker]

PULSE AMD Radeon™ RX 6500 XT 8GB

<p>Up to 2855 MHz, 8GB/64 bit DDR6. 18 Gbps Effective</p>

www.sapphiretech.com

¯\_(ツ)_/¯

I didn't chase it down to see if I could ever buy it.

Radeon RX 6500 XT 8GB Only Costs $20 More Than 4GB Version

Double the VRAM for 10% more

www.tomshardware.com

I saw the same stuff when I searched, but just out of curiousity, what I really wanted to see was a teardown of an 8GB board, to see where they put the extra VRAM. I guess with only two chips they won't have to resort to placing them on the back side of the board, though that may end up easier for Trace Routing, but I don't know.

 

[ryanjagtap]

Got a RDNA3 igpu review from ETA prime.

 

[jpiniero]

Asus TUF Gaming A16 mit Radeon RX 7600S im Test

Asus gegen den Rest der Welt: Mit dem TUF Gaming A16 samt Radeon RX 7600S stellt sich das bis dato einzige Notebook mit RDNA 3 dem Test.

www.computerbase.de

Laptop with the 7600S review. It's about 13% slower in the raster games they tested than the 4060 they compared it to, with both having the GPU power set to 80 W. I'd say it's not a disaster but not inspiring either.

 

[TESKATLIPOKA]

Asus TUF Gaming A16 mit Radeon RX 7600S im Test

Asus gegen den Rest der Welt: Mit dem TUF Gaming A16 samt Radeon RX 7600S stellt sich das bis dato einzige Notebook mit RDNA 3 dem Test.

www.computerbase.de

Laptop with the 7600S review. It's about 13% slower in the raster games they tested than the 4060 they compared it to, with both having the GPU power set to 80 W. I'd say it's not a disaster but not inspiring either.

So the full N33 will provide raster performance comparable to Ad107, but much worse RT performance.
Compared to 6800S(Full N23) the performance is also pathetic, barely any improvement.
Not seeing any reason to choose It over Ada. If It was built using 5(4)nm then at least perf/W would improve significantly, but It is using only the cheap 6nm process.

N32 could have pretty good raster performance, but RT will be another flop. I don't think a laptop with It will be that cheap either.

 

[moinmoin]

In many results it seems taking 6800S over 7600S (both at 80W TDP) may actually be slightly preferable. RDNA3 is such an insignificant gen so far.

 

[leoneazzurro]

Quite strange results going on there... I think they made some errors in testing here and there. I.e. the 6800S 80W faster than a 6800M 120W in Cyberpunk? Yeah, sure. Also quite strange the fact that we see such a difference with the same memory amount on AMD vs NV cards. First time I see that, and we should have seen it plenty in the 3060 8Gb/3070 8gb vs the 6600 (which should be affected as well), as it is in more than one game. Quite unique.
In any case, yes, N33 is not a groundbreaking improvement over N23, even if this is not the full die.

 

[ryanjagtap]

Not to be nitpicky, but the 7600S (28 CU) is a replacement for 6700S (28 CU) not 6800S (32 CU).
It has a TDP range of 50-75W. The 90W is already running the AMD equivalent of Nvidia dynamic boost. The 6800S has max TDP of 100W.
AMD has not changed much in N33 die with respect to N23 die. It's still 6nm, so the 25% improvement from just architecture change is ok (zen 2 to zen 3 on same node had 19% improvement). We are still getting the performance of the highest previous gen tier for this 'S' variant of GPU.

Not saying this is a great card, but it's not that bad a card to disparage as well. It's just..... Meh

 

[AtenRa]

70CUs would indicate 5 Shader engines enabled with 14CUs per shader engine instead of the full 6 SE + 16CUs per SE of the top model. That is quite a cut down part.

So I presume the spec would be as follows if this cut was also used as a GPU (possibly 7800XT IMO)

64MB L3
16GB GDDR6
70 CUs
70 RTcores
160 ROPs
280 TMUs.
640 GB/s bandwidth if 20 Gbps ram is used

Give it a 2.5-2.6ghz boost clock and it should perform a bit ahead of the 6950XT. Possible it gets released as a 7800XT but I expect AMD would much rather make N32 work as the 7800XT by increasing clocks to 3Ghz as they would be similar in performance and the N32 part would cost less to make.

No way NV32 can match the NV31 with the above specs.

NV32 will be used on the 7700XT and bellow.

 

[Timorous]

No way NV32 can match the NV31 with the above specs.

NV32 will be used on the 7700XT and bellow.

60CUs Vs 70CUs is not that much different and if N32 clocks better performance could be quite close. We are talking a 15% delta so around 2.9Ghz for New Vs 2.5Ghz for the N31 design would give you equal compute, texture fillrate and RT performance.

4 MCDs means both would have the same cache and memory bandwidth to go with that compute.

3 SEs Vs 5SEs means N31 version would have more rops and even with the clockspeed delta it would be ahead in this department but that would only show in cases where you were pixel fillrate limited.

So yea. Both would be pretty close in performance with just a 15% clockspeed advantage for N32 Vs that spec N31.

 

[jpiniero]

but It is using only the cheap 6nm process.

Compared to N5/4, yeah, but AD107 is 35% smaller. That's still not enough for AD107 to be cheaper but I'm sure it helps. Maybe AMD will get lucky and the wafer prices gap between N7/6 and N5/4 will widen.