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Discussion AMD Cezanne/Zen 3 APU Speculation and Discussion

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yuri69

Member
Jul 16, 2013
111
123
116
It looks like that Van Goth has 256bit DDR5.
lol, this is hilarious.

The DDR5 standard brings 2*32b channels per DIMM. Prior gens got just a single 64b channel. So a two-slotted Van Gogh still featurs a 128b bus - this time split as 2*2*32b and not 2*64b.

A quick googling reveals the reporting mechanism used by the AMD driver is rather simplistic. It simply reports the bus width as detected number of channels multiplied by a constant. For APUs this constant is set to 64b. Therefore this constant is not compensated for DDR5's 32b channels...

RadeonOpenCompute GitHub

// edit: my bad, I forgot Van Gogh uses RDNA => GFX10. So that GFX9 code doesn't apply, but the DDR5 thing does.
 
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Hans de Vries

Senior member
May 2, 2008
256
564
136
www.chip-architect.com
lol, this is hilarious.

The DDR5 standard brings 2*32b channels per DIMM. Prior gens got just a single 64b channel. So a two-slotted Van Gogh still featurs a 128b bus - this time split as 2*2*32b and not 2*64b.

A quick googling reveals the reporting mechanism used by the AMD driver is rather simplistic. It simply reports the bus width as detected number of channels multiplied by a constant. For APUs this constant is set to 64b. Therefore this constant is not compensated for DDR5's 32b channels...

RadeonOpenCompute GitHub

// edit: my bad, I forgot Van Gogh uses RDNA => GFX10. So that GFX9 code doesn't apply, but the DDR5 thing does.
You are looking at the wrong code here that is explicitely used to determine proporties of HBM memory which has 8 128bit channels per stack or 16 64bit (pseudo) channels.

Both LPDDR4 and LPDDR5 use 16 bit channels.
 
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IntelUser2000

Elite Member
Oct 14, 2003
7,337
1,994
136
Low end and quad channel/256-bit memory makes no sense.

Early rumors had Van Gogh being a chip for 15W parts, and Remembrandt taking the higher power range.

Maybe they want Van Gogh to be a true portable x86 gaming chip, but neither on-package HBM nor 256-bit memory channels signal cheap.

There's a reason iGPUs do not have many channel memory or HBM. It's to reduce cost.

If we ever see such an "iGPU" expect prices to be commensurate to it's performance. The major appeal of an iGPU is low prices and low power.

We're calling for super high end iGPUs now? Well how receptive were people to Kabylake-G?
 

scineram

Member
Nov 1, 2020
86
67
51
DDR5 is two channels per DIMM. But those are 32 bit. So this could really be a misreport.
Either way I am just glad VG is not cancelled.
 

burninatortech4

Senior member
Jan 29, 2014
353
94
101
There is a video

mmmm he installed the Vega 8 driver but im not convinced it is Vega 8, yet, i hope it is.
I think this is slightly misleading. The 5300G is Zen 2 (Cezzane). The 5400G is the low end Zen 3 (Lucienne). That's the chip we need to keep an eye out for.

I'm not shocked that the 5300G isn't significantly faster than the 4350G. Cezzane and Renior are essentially the same chip.

Source: AMD's Ryzen 5000 Lucienne: Not Simply Rebranded Ryzen 4000 Renoir (anandtech.com)
 

Shivansps

Diamond Member
Sep 11, 2013
3,180
812
136
Low end and quad channel/256-bit memory makes no sense.

Early rumors had Van Gogh being a chip for 15W parts, and Remembrandt taking the higher power range.

Maybe they want Van Gogh to be a true portable x86 gaming chip, but neither on-package HBM nor 256-bit memory channels signal cheap.

There's a reason iGPUs do not have many channel memory or HBM. It's to reduce cost.

If we ever see such an "iGPU" expect prices to be commensurate to it's performance. The major appeal of an iGPU is low prices and low power.

We're calling for super high end iGPUs now? Well how receptive were people to Kabylake-G?
Kaby-G was not really a IGP, it was a full GPU on die with HBM memory. That was super expensive.

In case of APUs im not sure how much more complicated will they be, they are selling 256bits GDDR6 SoCs to Sony and Microsoft right now and they arent super big or expensive.
In desktop you have the problem of needing a bigger socket what makes it highly unlikely for mainstream.

As for VG, the same log points out at having 8 CPUs, im just not sure if that means quad core + HT or that it is a octa with smt disabled.
 

moinmoin

Platinum Member
Jun 1, 2017
2,369
2,941
106
I think this is slightly misleading. The 5300G is Zen 2 (Cezzane). The 5400G is the low end Zen 3 (Lucienne). That's the chip we need to keep an eye out for.

I'm not shocked that the 5300G isn't significantly faster than the 4350G. Cezzane and Renior are essentially the same chip.

Source: AMD's Ryzen 5000 Lucienne: Not Simply Rebranded Ryzen 4000 Renoir (anandtech.com)
The article is talking about the segmentation in the low power mobile U-series. That's very unfortunate if AMD indeed reuses that segmentation in the desktop G-series as well.
 

jpiniero

Diamond Member
Oct 1, 2010
9,047
1,743
126
The article is talking about the segmentation in the low power mobile U-series. That's very unfortunate if AMD indeed reuses that segmentation in the desktop G-series as well.
Is the desktop version even going to be released any time soon (even if it's OEM only)? Cezanne laptops are MIA still.
 

moinmoin

Platinum Member
Jun 1, 2017
2,369
2,941
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Is the desktop version even going to be released any time soon (even if it's OEM only)? Cezanne laptops are MIA still.
No idea about the desktop parts. Though it should be very clear by now DIY market sales are not AMD's priority at all if the dies can be used in the OEM/ODM market instead.

Availability of Cezanne laptops actually seems to improve Germany. All ASUS models (7) are readily available, and the total amount of models (including other manufacturers not in stock yet) listed is at 59, with an additional 26 models using Lucienne (also 7 of them readily available).
 

jpiniero

Diamond Member
Oct 1, 2010
9,047
1,743
126
No idea about the desktop parts. Though it should be very clear by now DIY market sales are not AMD's priority at all if the dies can be used in the OEM/ODM market instead.

Availability of Cezanne laptops actually seems to improve Germany. All ASUS models (7) are readily available, and the total amount of models (including other manufacturers not in stock yet) listed is at 59, with an additional 26 models using Lucienne (also 7 of them readily available).
Ah interesting because there is basically nothing in the US. Best Buy has a single Lucene laptop in stock but that was all I could find for 5000 series. You can buy Renoir just fine.
 

Insert_Nickname

Diamond Member
May 6, 2012
3,983
585
126
Is the desktop version even going to be released any time soon (even if it's OEM only)? Cezanne laptops are MIA still.
AMD is selling like hotcakes to OEMs, so if DIY desktop ever gets Cezanne it'll be after OEMs have bought their share. You can only buy Renoir desktop APU unofficially, so I doubt the situation is going to improve before autumn, if that. With the pandemic going on, one might as well read tea leaves, or coffee grinds currently.
 

IntelUser2000

Elite Member
Oct 14, 2003
7,337
1,994
136
Kaby-G was not really a IGP, it was a full GPU on die with HBM memory. That was super expensive.
It meets all the definitions of an iGPU. Think about it, they won't put such massive GPUs on-die anyways so it'll end up being on a separate die. That's essentially Kabylake-G.

Consoles are on break even or even a slight loss so they are different.



So even on desktops they are playing the two core(Lucienne/Cezanne) game?
 

mikk

Diamond Member
May 15, 2012
3,086
913
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Availability of Cezanne laptops actually seems to improve Germany. All ASUS models (7) are readily available, and the total amount of models (including other manufacturers not in stock yet) listed is at 59, with an additional 26 models using Lucienne (also 7 of them readily available).

Asus is the only OEM with Cezanne at the moment, it's like they have an exclusive deal with AMD. It's always the same after a mobile AMD launch, 1-2 OEMs get some exclusive chips and then the real market availability follows 6 months later. Another slow AMD follow up mobile launch.
 

moinmoin

Platinum Member
Jun 1, 2017
2,369
2,941
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Asus is the only OEM with Cezanne at the moment, it's like they have an exclusive deal with AMD. It's always the same after a mobile AMD launch, 1-2 OEMs get some exclusive chips and then the real market availability follows 6 months later. Another slow AMD follow up mobile launch.
Your impression doesn't match reality in Germany then.
Geizhals right now lists 61 models with Cezanne, by ASUS, Acer, Lenovo and HP. ASUS is in stock, Acer appears to launch in early May, Lenovo is said to ship within 1-2 weeks, only the HP models are without any date so far.
 

Hans de Vries

Senior member
May 2, 2008
256
564
136
www.chip-architect.com

Hans de Vries

Senior member
May 2, 2008
256
564
136
www.chip-architect.com
In case of APUs im not sure how much more complicated will they be, they are selling 256bits GDDR6 SoCs to Sony and Microsoft right now and they arent super big or expensive.
In desktop you have the problem of needing a bigger socket what makes it highly unlikely for mainstream.

As for VG, the same log points out at having 8 CPUs, im just not sure if that means quad core + HT or that it is a octa with smt disabled.
With 8 RNDA2 CU's van Gogh will have about half the graphics performance of the XBOX series S in higher TDP SKU's. The memory interface is LPDDR4X and LPDDR5.

So a 256 bit interface should be expected I think with probably soldered memory chips. The iPhone's M1 has a 128bit LPDDR4x bus. Van Gogh would need 4 LPDDR packages instead of 2.

Screenshot_20210327-070337_Firefox.jpg

If van Gogh has a single Zen2 CCX then it would be only ~130-140mm²

20210327_063238.jpg
 
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Shivansps

Diamond Member
Sep 11, 2013
3,180
812
136
Thats along the lines of what im thinking, a APU with a high performance IGP for embedded applications, custom consoles and notebooks. This is also the kind of stuff you want to on ITX format, low-power/solar powered PC.

Either that or this is just a reporting mistake and VG is just a boring Raven2 replacement, but in that case i dont see a point in removing DDR4/DDR5 support.
 

moinmoin

Platinum Member
Jun 1, 2017
2,369
2,941
106
On the leaked roadmap Van Gogh includes the tag CVML and starts a new lane that sits between the current desktop and mobile chips. So it does seem to be a new line of specialized chips, which has to be for some higher margin market like embedded.
 

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