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

 

[soresu]

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


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.

Considering how reliant RT is on memory I wonder how well this would play out at equal TFLOPS?

 

[Martimus]

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.

SAM wasn't enabled on their testing with the 3080 and 6800XT. They only enabled it on the 3090 to 6900XT chart.

 

[blckgrffn]

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

I feel the exact same way. Also, I have a really solid 650W PSU and that 6800 XT is recommending a 750W PSU... clearly that means 750W if you have a Cougar/lower end Corsair/EVGA/Seasonic unit, right? :/ Or are pairing it with an i9?

 

[sze5003]

For the 6900xt I assume it's full potential will be better if you have an amd card and board right?

Although for pure gaming use I'm not sure if that would matter much.

 

[soresu]

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?

The presenter/engineer mentioned that it was modelled on Zen3's L3 cache.

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

Makes me wonder if CP 2077 delay has DXR 1.1 zero day goodies in store.

 

[Greyguy1948]

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?

It looks like eDRAM cache. Intel and IBM used/are using it. Transistor count is "only" 28 billion so any transistor cache is smaller.
EDRAM on Wiki

 

[moinmoin]

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.

First time I saw it posted, good video.

Infinity Control Fabric sounds like the Scalable Control Fabric is being expanded outside the device (I imagine that's also part of Infinity Architecture), allowing different devices to know of each other's state and sensors. This may explain why SAM requires Ryzen 5000. This also raises the possibility that RDNA2 reuses the Infinity Fabric hierarchy already known from the Zen CPUs (with Scalable Control Fabric monitoring and controlling everything while Scalable Data Fabric connects all the parts for I/O), with Infinity Cache working the same way as L3 cache in Zen CPU, that is as essentially a crossbar between all cores (= CUs in RDNA2's case).

 

[MrTeal]

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.

Maybe in 2003. The only people playing at 720 are people trying to play shooters at 350FPS and people stuck with 768p laptop screens.

 

[Konan]

Oh... using Rage mode voids the warranty

 

[amenx]

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

No it isnt. At least not to anyone with a discrete GPU today. And most certainly not for ppl with $500+ GPUs.

 

[Hitman928]

Oh... using Rage mode voids the warranty

View attachment 32529

I wouldn't worry about it. As long as you're giving the card decent ambient air, there shouldn't be any issues. Pretty sure this statement is there to cover people using Wattman to crank voltages to crazy levels. Also not sure rage mode even counts as overclocking but maybe AMD can clarify.

 

[moinmoin]

Oh... using Rage mode voids the warranty

View attachment 32529

"AMD has clarified that Rage Mode does not void the warranty."

AMD Radeon 6000 series takes the GPU crown - SemiAccurate

www.semiaccurate.com

Kind of an odd mistake to make and miss, but certainly better that way.

 

[Hitman928]

"AMD has clarified that Rage Mode does not void the warranty."

AMD Radeon 6000 series takes the GPU crown - SemiAccurate

www.semiaccurate.com

Kind of an odd mistake to make and miss, but certainly better that way.

And there you go, AMD quick to squash that one.

 

[moinmoin]

Heh, all those shades...

 

[Vope45]

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.

Is this a joke ?

 

[Hitman928]

Is this a joke ?

I think so.

 

[richierich1212]

Yep I had two of those in CF lol.

View attachment 32522

With the rice crackers to boot!

 

[n0x1ous]

interesting that the spec page on amd recommends 850w psu for 6900xt but 750w for 6800xt when they are both rated at 300w tdp

 

[beginner99]

Heh, all those shades...

+1 for edge connectors. WIth these larhe cards having connectors at back would just be annoying.

To something completely different: Anyone else thought that die shot looks like you could just "cut-it" in the middle and have 2 40 CU dies, erm, chiplets?

With all the trade-off the cache has, it's probably needed for chiplet gpus and solves (or at least softens) the iGPU memory bandwidth issue at the same time. While it's a trade-off got these high end GPUs, the tech itself make a ton of sense in this bigger picture.

Else pricing as expected, 6800 actually a bit high. Supply will probably be very limited else the 6800 at $500-530 would have made a bit more sense. Thats probably the downside of the small bus, can't cut it even on the 6800 and hence need the full 16GB vram.

Anyway, these are all out of my league anyway.

 

[n0x1ous]

I don't like the naming. XT has always meant full die for Radeon in the past.

Would have preferred 6900 XT, 6900 PRO, 6900 (9 signifying Navi 21 biggest die)

then maybe a 6900 XTX with AIO cooler

 

[Saylick]

To something completely different: Anyone else thought that die shot looks like you could just "cut-it" in the middle and have 2 40 CU dies, erm, chiplets?

It makes the most sense in my mind to have each Shader Engine be its own chiplet when AMD moves RDNA to a chiplet architecture. The Shader Engine has all of the complete parts to run the graphics pipeline so its the most basic building block that gets duplicated. The memory controllers, last-level cache (Infinity Cache), display connectors, codec engines, etc can be on an IO die. This approach pretty much mirrors how it's done on Zen 2/3.

https://twitter.com/x/status/1321508972780609536

 

[Vope45]

I don't like the naming. XT has always meant full die for Radeon in the past.

Would have preferred 6900 XT, 6900 PRO, 6900 (9 signifying Navi 21 biggest die)

then maybe a 6900 XTX with AIO cooler

Because Navi introduced scalability.

 

[randomhero]

Very good showing AMD! I would count this as their zen2 moment in graphics.
And inf cache! I knew right from the moment RGT leaked that(their source is definitely AMD) it was true. It was so way out there, typical AMD!

 

[Konan]

"AMD has clarified that Rage Mode does not void the warranty."

AMD Radeon 6000 series takes the GPU crown - SemiAccurate

www.semiaccurate.com

Kind of an odd mistake to make and miss, but certainly better that way.

That is soo good to hear! thanks for that

 

[Krteq]

https://twitter.com/x/status/1321528253539123200