AMD Renoir APUs Bringing "DCN 2.1" Display Engine

[phoronix]

Phoronix: AMD Renoir APUs Bringing "DCN 2.1" Display Engine

Raven Ridge APUs brought the DCN 1.0 "Display Core Next" engine, Navi GPUs upped that to a DCN 2.0 implementation for the display engine, and now the Renoir APUs are ushering in DCN 2.1. This is a bit interesting particularly with Renoir being a Vega-based GPU and not Navi as one would have hoped prior to the Vega confirmation in the earlier patches...

http://www.phoronix.com/scan.php?page=news_item&px=AMD-Renoir-DCN-2.1-Patches

[shmerl]

Why did they pick Vega instead of Navi for 7 nm APUs?

[tildearrow]

Why did they pick Vega instead of Navi for 7 nm APUs?

AMD always does this with mid-range/lower-end products. They re-use previous architectures for years.
Maybe to save costs.

[LoveRPi]

Renoir may not be a monolithic chip. It may end up being a 7nm CPU + 12nm GF GPU+IO chip or some similar configuration on the same substrate. Navi is a 7nm architecture designed for TSMC and Vega is both 7nm TSMC and 12nm GF.

[shmerl]

Because top Vega products like Radeon Instinct MI50/MI60 and Radeon VII were done and proven on 7 nm too, even before Navi come... so why not

Because Navi is supposed to be more power efficient. "Accidentally" a very important point for APUs.

[LoveRPi]

Because Navi is supposed to be more power efficient. "Accidentally" a very important point for APUs.

Navi is not more power efficient. It works on a smaller group operating unit than Vega. The wider Vega has higher power efficiency. Nvidia goes very very wide for power efficiency in graphical workloads. Navi was designed to go in everything from phones to supercomputers and has a smaller group operating unit.

[cb88]

Navi is not more power efficient.

That's just blatantly wrong, the whole point of Navi is to improve performance / watt and it is much more efficient for graphics than Vega, however.... mobile vega was always where vega shined as it wasn't trying to hit high clocks and could run efficiently... the same will be true for Navi when it is integrated into APUs but it obviously is not ready for that... if you want OEMs to sign on you have to have a stable, low effort to maintain chipset... and Navi just doesn't fit there yet as it is really just barely off the drawing board and from what rumors we have heard we know that Navi will see a significant revision by next year to address raytracing and improve performance further. It's likely we won't see Navi based APUs untill the architecture has time to settle and become a little more stable.

The only task at which Vega is more efficient than Navi is compute... and there are categories of branchy compute that Navi will excel at... Vega is the datacenter architecture and Navi is the gaming architecture. Apples and oranges... except that in this case you said Vega is mor efficent but we are talking about and APU wher ete main task is going to be graphics, with perhaps some light compute work on the side... which mean it isn't vega's efficiency they chose it for, because it is less efficient for this task, they chose it because it is stable and well understood how it will perform.

[finalzone]

Why did they pick Vega instead of Navi for 7 nm APUs?

Renoir is basically an evolution of Raven Ridge.

[yokem55]

Yeah, It's a pretty good guess that Renior is Vega based due to obligations to Sony and MS. The last thing MS and Sony want to deal with is another party beating them to market with mostly the same hardware.

[stebler]

LPDDR4 is mentioned in this patch. https://lists.freedesktop.org/archiv...st/039227.html