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ronch
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Blotchy Structures in Ryzen Die Shots

Wed Jun 17, 2020 12:50 am

Am I the only one who's going to point out that if you look at die shots of current AMD processors there seems to be so many 'blotches'? This is true for the cores themselves and many blocks of the surrounding logic, which look even 'blotchier'. This seems to be a characteristic of AMD's high density library which they began using with Bulldozer (I noticed this blotchy structure in Zambezi in the Vcc Gating Footer next to the core, and this has been an increasingly common sight in Steamroller and Excavator, and even more so with Summit Ridge.

I'm sure Intel has noticed this also and may be planning something similar in their top secret future CPU core, if they feel that this design philosophy has advantages over traditional methods. I've been staring at die shots in my sleep so when Zen came out I've been almost baffled by the die shots. They're nothing like die shots from earlier integrated circuits, CPU or otherwise. Very curious.

Would also be interesting to see some microscopic shots of these blotchy (from afar) structures.

Edit - feel free to click on the images below for more detail. Look at those features. It's like someone vomited all over the CPU die!! Sorry I know it's gross but that's what comes to my mind. Someone psychoanalyze me! Lol

Image

Image
Last edited by ronch on Wed Jun 17, 2020 5:18 am, edited 1 time in total.
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Re: Blotchy Structures in Ryzen Die Shots

Wed Jun 17, 2020 1:41 am

Interesting. I had not looked at Ryzen die shots previously. The blotchy areas look kind of like satellite photos of the Earth's surface!

Just a WAG: This could be an effect of using automated routing tools. FWIW, from my (brief) stint doing FPGA work a few years back, the routing algorithm is actually pseudo-random. It uses a RNG and some heuristics to do many trial placements of logic blocks, searching for an optimal fit where all of the timing requirements are met. I imagine this would result in a "blobby" placement of logic elements, where circuits which have the most critical timing dependencies on each other would tend to clump together in ways which minimize the average distance between components.

The more regular looking areas are caches, or (possibly) SIMD execution units, which consist of many repeated instances of the same circuitry.
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Redocbew
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Re: Blotchy Structures in Ryzen Die Shots

Wed Jun 17, 2020 1:58 am

That would make sense. It's like a precursor to machine learning that's used to build the machine. :o
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Wirko
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Re: Blotchy Structures in Ryzen Die Shots

Wed Jun 17, 2020 3:24 am

There are similar-looking structures in Intel chips, too. Here's Skylake: https://www.flickr.com/photos/130561288@N04/39024590565
 
ronch
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Re: Blotchy Structures in Ryzen Die Shots

Wed Jun 17, 2020 5:29 am

@Wirko

Good catch! I have die shots of Intel chips but they aren't very high res so I never noticed those. Very interesting to note this is becoming a trend, maybe not just with AMD and Intel, although AMD is obviously using it far more extensively. I'd be curious to know if new mobile ARM cores like the A76 and Apple A13 use these high density libraries as well, which wouldn't be far-fetched considering they have to fit these cores into tiny dies and use as little power as possible.

Too bad Fritz's images can't be saved. They're priceless. Really good micro-photography.
NEC V20 > AMD Am386DX-40 > AMD Am486DX2-66 > Intel Pentium-200 > Cyrix 6x86MX-PR233 > AMD K6-2/450 > AMD Athlon 800 > Intel Pentium 4 2.8C > AMD Athlon 64 X2 4800 > AMD Phenom II X3 720 > AMD FX-8350 > RYZEN?
 
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Re: Blotchy Structures in Ryzen Die Shots

Wed Jun 17, 2020 11:17 am

ronch wrote:
@Wirko

Good catch! I have die shots of Intel chips but they aren't very high res so I never noticed those. Very interesting to note this is becoming a trend, maybe not just with AMD and Intel, although AMD is obviously using it far more extensively. I'd be curious to know if new mobile ARM cores like the A76 and Apple A13 use these high density libraries as well, which wouldn't be far-fetched considering they have to fit these cores into tiny dies and use as little power as possible.

Too bad Fritz's images can't be saved. They're priceless. Really good micro-photography.

Inspect -> open image in new tab. https://live.staticflickr.com/4610/3902 ... 997_6k.jpg
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Captain Ned
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Re: Blotchy Structures in Ryzen Die Shots

Wed Jun 17, 2020 11:41 am

Well, so much for the Intel chips in "The Last Mimzy".
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ronch
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Re: Blotchy Structures in Ryzen Die Shots

Wed Jun 17, 2020 9:46 pm

@Waco - awesome!! Many thanks!!!
NEC V20 > AMD Am386DX-40 > AMD Am486DX2-66 > Intel Pentium-200 > Cyrix 6x86MX-PR233 > AMD K6-2/450 > AMD Athlon 800 > Intel Pentium 4 2.8C > AMD Athlon 64 X2 4800 > AMD Phenom II X3 720 > AMD FX-8350 > RYZEN?
 
ronch
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Re: Blotchy Structures in Ryzen Die Shots

Sat Jul 04, 2020 8:31 pm

Found some more tidbits regarding these mushy structures.

https://www.realworldtech.com/forum/?th ... tid=186106

That page above has tons of stuff to dig through but it also lead me to dig a bit on Intel's new Atoms and it seems the Atom x7 (Cherry Trail) used in the Surface 3 also has lots of these blotchy structures. Seems this is the trend with not just Ryzen but mobile chips, as density and power efficiency take precedence over sheer clock speeds.

https://www.anandtech.com/show/9219/the ... 3-review/4

Take note, the Anandtech article dates back to 2015, so Intel apparently has had this high density thing going on about the same time AMD started using them with Bulldozer-derived cores, except Intel's doing it on a smaller process node.

Would be cool to find some die shots of current ARM cores but ARM is notorious for not giving out die shots, at least their partners are.
NEC V20 > AMD Am386DX-40 > AMD Am486DX2-66 > Intel Pentium-200 > Cyrix 6x86MX-PR233 > AMD K6-2/450 > AMD Athlon 800 > Intel Pentium 4 2.8C > AMD Athlon 64 X2 4800 > AMD Phenom II X3 720 > AMD FX-8350 > RYZEN?

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