Question AMD Rembrandt/Zen 3+ APU Speculation and Discussion

[izaic3]

Alright, so we've had some leaks so far. I don't know if any of it's been confirmed yet, as it's pretty early, but here is what I've surmised so far (massive grain of salt of course):

• Zen 3 "enhanced"
• DDR5 and LPDDR5 support
• PCIE4
• 6nm
• CVML
• Navi 2/RDNA/RDNA 2
• 12 CU
• Socket FP7/AM5
• Possible USB4
• 2021(unlikely) -2022 (more likely) release date

If if turns out to have RDNA 2 and 12 CU, I could see iGPU performance potentially almost doubling over Cezanne.

If I've made any mistakes or gotten anything wrong, please let me know. I'd also love to hear more knowledgeable people weigh in on their expectations.

 

[Shivansps]

I think we overstimate the amount of bandwidth the CPU part needs for gaming tasks, i would not worry too much about it on RMB.

This is clear on Cezanne, the APU cpu cores doubled and performs faster, yet, as long as the IGP can keep up, it still performs better than a 3400G with the same ram configuration.

 

[Gideon]

I still think Rembrandt will be extremely good overall, but the inclusion of a small 16MB IC would be enough I'd think to just solidify it's position as an entry 1080p solution.

In My dreams it would have 16MB IC and room reserved for TSVs, so that a stacked premium APU could be offered that would have:

• Another 16MB of IC, but ideally stacked in a "checkerboard way" on top of the CUs while extra (12? )CUs would be stacked above the cache on the primary die
• Additional 16MB of L3 for the CPUs (bringing parity to non-stacked desktop CPUs)

They would have to lower GPU clocks of-course but the added CUs and cache should more than make up for that.

All in all, it would allow a thin and light laptop with midrange GPU levels of 1080p preformance. This would have it's niche even if the APU alone would cost €500+

 

[Shivansps]

If they can make the 12CU to work OK with around 100Gb/s why would they add an IC/L4/3D Cache to it? Im guessing that if RMB has 12 CUs it is because it can use them with expected DDR5/LPDDR5 specs.

The Navi24 (RX6300) isnt expected to be a 16 CU RDNA2 with just 128GB/s and a 16MB IC? RMB with good memory may perform really close to Navi24.

 

[eek2121]

All this talk makes me super hyped for the Steam Deck. can’t wait for release.

 

[Gideon]

If they can make the 12CU to work OK with around 100Gb/s why would they add an IC/L4/3D Cache to it? Im guessing that if RMB has 12 CUs it is because it can use them with expected DDR5/LPDDR5 specs.

The Navi24 (RX6300) isnt expected to be a 16 CU RDNA2 with just 128GB/s and a 16MB IC? RMB with good memory may perform really close to Navi24.

Yeah, I figured the same. That's why I thought that also adding stacked CUs would make it worthwhile (you already have tons of otherwise dead silicon on top die).

Putting cache on top of CUs and CUs on top of cache would make it a pretty serious GPU (needs IC on bottom die though).

Wishful thinking I know, but one can dream!

 

[moinmoin]

Considering the more fully featured Van Gogh predates RMB I get the feeling that for its main APU line AMD still errs on cut-down designs optimized for low power instead for features. At the same time the yearly cadence seems to be important to them which allows them to relatively quickly add and update parts.

I would wish for a more fully featured APU as well. But I guess unless demand for the line started by Van Gogh explodes and requires updates in core and CU count, the regular APU line will get to the state we want in a couple years.

 

[leoneazzurro]

So Rembrandt is already in production and on schedule for CES

https://twitter.com/x/status/1433797143328800775

 

[movdx]

@uzzi38: Rembrandt won't be presented at CES? Or to rephrase even if it is revealed when it will be available?

 

[jpiniero]

Or to rephrase even if it is revealed when it will be available?

When OEMs feel like it? I'll point out that we are talking about mobile only.

 

[moinmoin]

The desktop RMB likely will be launched together with the AM5 platform, which I expect to happen closer to the launch of Zen 4 (whenever that is).

 

[Joe NYC]

Is there any consensus if Rembrandt is a monolithic die or chiplet based?

 

[jpiniero]

Is there any consensus if Rembrandt is a monolithic die or chiplet based?

Def monolithic.

 

[uzzi38]

@uzzi38: Rembrandt won't be presented at CES? Or to rephrase even if it is revealed when it will be available?

There's a non-zero chance it won't be. I dunno, it's a bit of a stretch of a rumour still, I say see how things pan out a bit more.

 

[movdx]

When OEMs feel like it? I'll point out that we are talking about mobile only.

Mobile only for sure. Judging from how the roll-out and availability of cezanne is if I was OEM I would put Rembrandt out ASAP

 

[soresu]

The desktop RMB likely will be launched together with the AM5 platform, which I expect to happen closer to the launch of Zen 4 (whenever that is).

Bare in mind that Raphael is reportedly potentially an APU itself.

We may not even see Rembrandt outside of soldered/embedded/mobile platforms.

Unless of course the fab capacity of N5/N5P becomes the deciding factor, which is certainly a significant possibility for the time being.

 

[scineram]

Bare in mind that Raphael is reportedly potentially an APU itself.

We may not even see Rembrandt outside of soldered/embedded/mobile platforms.

Unless of course the fab capacity of N5/N5P becomes the deciding factor, which is certainly a significant possibility for the time being.

Nah, you will. AMD will want and need some cheap stuff on AM5 for low end.

 

[uzzi38]

Bare in mind that Raphael is reportedly potentially an APU itself.

We may not even see Rembrandt outside of soldered/embedded/mobile platforms.

Unless of course the fab capacity of N5/N5P becomes the deciding factor, which is certainly a significant possibility for the time being.

It'll come to desktops too.

 

[moinmoin]

Bare in mind that Raphael is reportedly potentially an APU itself.

I guess we'll need to make a difference between mobile and desktop APUs from here on out. The Ryzen APUs so far exist to be competitive in the mobile market, i.e. with competitive integrated graphics performance. I don't expect that to happen with Raphael. There graphics performance is not the issue, instead having graphics at all has been the competitive advantage Intel desktop chips enjoyed over Ryzen CPUs so far that Raphael appears to put an end to.

 

[DrMrLordX]

Raphael - if it gets an iGPU - won't be monolithic since it will still likely use CCDs from Genoa.

 

[Shivansps]

It really depends on how AMD does it, it is a iGPU on the I/O die or RDNA3 chiplets on SoC, in either case they will be able to use V-CACHE as a IC? thats the key. If it is chiplets then AMD may be looking into not using mobile chips on desktop except maybe for the low end.

If it is on the I/O die, then i expect to be something small, then again a several components are needed in order to make the GPU to work, it is worth it to make all that only to give it, lets say, 2CUs?

RDNA3 chiplets seems too early for Raphael i think.

 

[LightningZ71]

VCache between chiplets for APUs on a mobile aimed product is a non-starter without very advanced interconnect strategies. Leaving the chiplets to communicate with anything is a very power intensive act, and a VCache, especially one acting as iCache, would be hit a lot!

 

[Shivansps]

Raphael should not be a mobile oriented product, they have RMB for that.

 

[jpiniero]

If it is on the I/O die, then i expect to be something small, then again a several components are needed in order to make the GPU to work, it is worth it to make all that only to give it, lets say, 2CUs?

Between 3-6, with more likely at the lower end.

 

[ahimsa42]

if Rembrandt comes out in early 2022, is it possible that Phoenix with zen 4 will be available in late 2022? if possible, i would think it may be worth it to wait for ryzen 7000.

 

[moinmoin]

if Rembrandt comes out in early 2022, is it possible that Phoenix with zen 4 will be available in late 2022? if possible, i would think it may be worth it to wait for ryzen 7000.

The mobile APU line follows a yearly cadence.