AMD shows off stacked 3D V-Cache chiplets, resulting in up to 192MB of L3 cache

Shawn Knight

Posts: 13,274   +132
Staff member
In brief: AMD caught everyone off guard at Computex 2021 with a demonstration of its new 3D chiplet technology that looks to deliver the type of performance gain you’d typically see with a new process node or microarchitecture.

Developed in collaboration with TSMC, AMD’s first application of the 3D chiplet tech is a vertical cache addition for its high-end processors. In a nutshell, AMD used a process called through-silicon vias (TSVs) to stack additional L3 cache on top of the compute chiplets.

AMD CEO Dr. Lisa Su showed off a prototype Ryzen 5000 CPU with one of two chiplets featuring the added stacked cache. As AnandTech highlights, the difference is obvious compared to the standard chiplet. The 3D V-Cache die is not as large as the core die, so AMD added additional structural silicon for support. Both dies were also thinned, meaning AMD doesn’t have to change up its heatspreader design.

According to AMD, the hybrid bond approach provides "over 200 times the interconnect density of 2D chiplets and more than 15 times the density compared to existing 3D packaging solutions."

AMD highlighted some of the performance gains using a standard Ryzen 9 5900X 12-core processor and one with the 3D V-Cache. The standard processor features 64MB of total L3 cache (32MB per chiplet) while the 3D V-Cache chip boosted this to a total of 192MB. With both CPUs fixed at 4GHz, the system with the new chip exhibited an average of 15 percent better gaming performance at 1080p.

  • DOTA2 (Vulkan): +18 percent
  • Gears 5 (DX12): +12 percent
  • Monster Hunter World (DX11): +25 percent
  • League of Legends (DX11): +4 percent
  • Fortnite (DX12): +17 percent

AMD said it is on track to begin production of processors with 3D V-Cache chiplets by the end of 2021.

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NeoMorpheus

Posts: 651   +1,204
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Lionvibez

Posts: 2,340   +1,874
They did mention this will be going to higher end models. So wonder how long before it comes down to desktop ryzen level. And is Zen 3+ going to be one of these ?
 

Kosmoz

Posts: 259   +461
They did mention this will be going to higher end models. So wonder how long before it comes down to desktop ryzen level. And is Zen 3+ going to be one of these ?
Tomshardware got this update a few hours ago:
"AMD has confirmed to that Zen 3 Ryzen processors with 3D V-Cache will enter production later this year."

This means it's gonna be a Zen3+ (refresh), which is great news and will probably KO Alder Lake :)

Link > https://www.tomshardware.com/news/a...mb-of-l3-cache-per-chip-15-gaming-improvement
 

Lionvibez

Posts: 2,340   +1,874
Tomshardware got this update a few hours ago:
"AMD has confirmed to that Zen 3 Ryzen processors with 3D V-Cache will enter production later this year."

This means it's gonna be a Zen3+ (refresh), which is great news and will probably KO Alder Lake :)

Link > https://www.tomshardware.com/news/a...mb-of-l3-cache-per-chip-15-gaming-improvement
Will have to wait and see what alderlake brings to the table. While Rocket Lake is kinda of a joke. Tigerlake on the laptop side competes well with Mobile Zen 3. So Intel can be competitive.
 

tellmewhy

Posts: 98   +49
Even alone as a new technology gives impressive increase in cache memory quantity but AMD chips they have and good cache prediction so it’s a very nice combo.
 

ypsylon

Posts: 365   +286
It's really the next logical step in CPU development. To get rid of the actual RAM as we understand it today. In truth we don't have to worry about big LGA pin-outs because after RAM slots are gone there will be more than sufficient space to accommodate bigger socket and reduce the circuitry required. Of course I understand it's only tiny step and proof of concept, but I'm all in on the idea. It easy to see how much memory matters on CPU when you compare 1xxx TR and 3xxx TR with its massive L3. Perhaps L3 is called a 'victim cache', but it is still mighty fast compared to RAM. Everything benefits from cache on chip. RAM is the most expendable expansion from all slots currently on the motherboard.

I'm amazed this didn't catch on first time when Intel flirted with it in was it Broadwell or whatever. I was very hopeful that AMD will deliver for the masses CPUs like some EPYC SKUs. Where you have limited number of cores, but 3 times the cache on chip vs nominal amount.

It's frankly amazing how AMD keynote was on point, just facts and figures and Intel was just yet again balloon of hot air without saying anything new, making irrational claims and couldn't even really focus on its own products.
 

neeyik

Posts: 1,877   +2,191
Staff member
I'm amazed this didn't catch on first time when Intel flirted with it in was it Broadwell or whatever.
Having more L3 cache doesn't help every application, though, and the cost of increasing the SRAM footprint in a monolithic design has to be balanced against the potential gain in sales.
It easy to see how much memory matters on CPU when you compare 1xxx TR and 3xxx TR with its massive L3.
The problem with comparing TR generations, to examine the impact of cache amounts, is that there are significant architectural changes between. This makes it quite a bit harder to pin down whether or not the larger cache footprint is helping matters.

Have a look at some of the test results in our 2nd gen TR review and directly compare the 2950X to the 1950X - they're both 16 core, twin die designs, and have the same amount of L3 cache (the former has a 10% boost clock advantage). Note how there's little difference between them in the PCMark, Excel, and VeraCrypt tests, and just 8% in the Z-zip results.

Pretty much what one would expect, given the changes between Zen and Zen+ were quite minimal.Now look at the 2990WX figures and, other than Z-zip decompression, it's slower across in the other 4 tests - even accounting for the lower clock speeds, it's clear the extra L3 cache isn't making any difference.

With the 3rd gen TR range, the huge performance gains between these models and the 2nd gen ones might give the impression that the even larger amount of L3 cache is making a big difference, but it's more a case of how the changes to the entire memory sub-system (e.g. the use of the IO chip) has improved matters.
 

JamesBlond

Posts: 98   +60
Well done AMD, this will make a massive change to all future computing, as L3 cache counts more than most, but lets get the L2 boosted which is most important.
 

DZillaXx

Posts: 281   +406
Will have to wait and see what alderlake brings to the table. While Rocket Lake is kinda of a joke. Tigerlake on the laptop side competes well with Mobile Zen 3. So Intel can be competitive.

In performance maybe.

But Performance per watt intel still has some way to go.
 

NeoMorpheus

Posts: 651   +1,204
So Intel can be competitive.
Nothing against you personally, but I really love how people turn a blind eye to all the illegal crap that Intel (and Nvidia) has done, how they held the industry back in what I call the 4 core hell and instead of cheering for AMD, Apple or anyone else with ARM CPUS to take over and finally kill Intel, people want them back on top....

Talk about Stockholm syndrome victims.
 

Lionvibez

Posts: 2,340   +1,874
Nothing against you personally, but I really love how people turn a blind eye to all the illegal crap that Intel (and Nvidia) has done, how they held the industry back in what I call the 4 core hell and instead of cheering for AMD, Apple or anyone else with ARM CPUS to take over and finally kill Intel, people want them back on top....

Talk about Stockholm syndrome victims.
This is kind of off topic since this article has nothing do to with intel and their shenanigans in the past. And I don't see a single post in here condoning that.

And Intel is too big and have far too much money and marketshare to just lay down and die. Competition is also good for the market it keeps prices down. Intel also does alot of things that aren't cpu's wanting them to die seems fan boyish.
 

NeoMorpheus

Posts: 651   +1,204
This is kind of off topic since this article has nothing do to with intel and their shenanigans in the past. And I don't see a single post in here condoning that.

And Intel is too big and have far too much money and marketshare to just lay down and die. Competition is also good for the market it keeps prices down. Intel also does alot of things that aren't cpu's wanting them to die seems fan boyish.
Then going completely off topic, two points from your reply:

1- Its off topic when is convenient to you.

2- Its not off topic because somehow, I am accused of fanboism. (here is a mirror for you, buddy)

Then I will add my third point, my original post is spot on, considering your reply.

And closing with an advice, defend a company that at the very least, uses lube on you before raping your wallet. Anti-consumer corporations dont need more white knights.
 
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Lionvibez

Posts: 2,340   +1,874
Then going completely off topic, two points from your reply:

1- Its off topic when is convenient to you.

2- Its not off topic because somehow, I am accused of fanboism. (here is a mirror for you, buddy)

Then I will add my third point, my original post is spot on, considering your reply.

And closing with an advice, defend a company that at the very least, uses lube on you before raping your wallet. Anti-consumer corporations dont need more white knights.
No its off topic because this has nothing to do with AMD's presentation.

I never said you were a fan boy I said trying to kill off the competition which would hurt the market due to there be less competitors is fan boy ish.

And it seems you just came here to pick a fight that you started on your own. The last statement is laughable because I'm on a AM4 platform.

Good day Sir!
 
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