Tuesday, August 23rd 2016

AMD ZEN Quad-Core Subunit Named CPU-Complex (CCX)

We've been chasing AMD Zen for a long time now. Our older report from April 2015 uncovered an important detail about component organization on Zen processors - the clumping of four CPU cores into a highly-specialized, possibly indivisible subunit referred to then, as the "Zen Quad-core Unit." Some of the latest presentations about the architecture, following AMD's "performance reveal" event from earlier this month, shed more light on this quad-core unit.

AMD is referring to the Zen quad-core unit as the CPU-Complex (CCX). Each CCX is a combination of four independent CPU cores. Unlike on "Bulldozer," a "Zen" core does not share any of its number-crunching machinery with neighboring cores. Each "Zen" core has a dedicated L2 cache of 512 KB, and four Zen cores share an 8 MB L3 cache. AMD will control core-counts by controlling CCX units. A "Summit Ridge" socket AM4 processor features two CCX units (making up eight cores in all), sharing a dual-channel DDR4 memory controller, and the platform core-logic (chipset), complete with an integrated PCI-Express root complex. Socket AM4 APUs will feature one CCX unit, and an integrated GPU in place of the second CCX. With this, AMD is able to bring the two diverse desktop platforms under one socket.
Source: Heise.de
Add your own comment

44 Comments on AMD ZEN Quad-Core Subunit Named CPU-Complex (CCX)

#26
qubit
Overclocked quantum bit
FrickIn the future it might come back in some form, when multithreaded loads are more common.
Noooo! They'd be shooting themselves in the foot if they did. I've never seen Intel do this and they have been the performance leaders for most of the time.
Posted on Reply
#27
HD64G
For anyone who request a dual core Zen for office use, just buy A6-A8 with AM4 that will be on sale soon. Or an even cheaper A6 today with cheaper mobo as well compared to AM4 ones. What's the point to go for Zen to use it in office work after all? We are talking about an enthusiast chip, don' t we?
Posted on Reply
#28
RejZoR
Single CCX unit CPU could be interesting. That would still be 4 cores, 8 threads. I wonder how would such CPU fare against current generation of AMD's octa cores...
Posted on Reply
#29
GhostRyder
Prima.VeraSorry but is not. I'm an office worker too, and I multitask like crazy. I have a laptop with an i7-dual Core Mobile (yeah, I know, f**ng Intel and its deceiving practices), and if I have Outlook open, several Word, Excel, PDF sessions, IE and Firefox windows and some apps open, the laptop becomes so sluggish, I can barely work. And if you also have some (shitty) Java apps or webpages, you're caput. CPU will go over 90% and the laptop it turns into a jet engine, both noise and heat wise.
I have had the exact same problem trying to explain that to people who are looking at them thinking they are they are just like the desktop and higher mobile i7's. Its confusing that Intel has so many sub categories for their chips with similar names. Its really a problem and causes so much confusion when trying to explain it to others at times.
64KFor a basic business PC it's all you need to run MS Office. Business is the biggest market for PCs.
Funny enough, most offices I go to now a days have basic i5's with a very small amount have Pentiums. I don't see i3's almost at all anymore except in regular desktops.

The new Zen sounds interesting enough, I hope for the most part we do get base model quads since at this day and age dual cores are just to little (Least in my opinion).
Posted on Reply
#30
cdawall
where the hell are my stars
Sihastru"Every core can access every cache with same average latency."

Isn't that like saying that the GTX 970 can access every memory with same average bandwidth? But leaving jokes aside, do they say if a CCX can access the L3 cache of another CCX? If not, I don't see how they can build a true 8 core CPU, but instead a 2P 4 core system with horrible cache latency issues.
I'm curious of the same. AMD also has a habit of having slow cache from the get go, which would just make this worse.
Posted on Reply
#31
TheoneandonlyMrK
cdawallI'm curious of the same. AMD also has a habit of having slow cache from the get go, which would just make this worse.
Read up as the cache is one if Amds main improvements and its 16 way linked so a module with 3 duff cores should still be able to use all of the l3 cache on die if its working, could make for snappy dual cores with massive l3 cache.
Posted on Reply
#32
Toothless
Tech, Games, and TPU!
They can give me a single core at 6ghz+ or they can buy me a 4P rig for rendering the Intel logo at 8k.

I have stuff that only needs one core that needs love.
Posted on Reply
#33
suraswami
How confused Windows will be now?
Posted on Reply
#34
newtekie1
Semi-Retired Folder
ShurikNWhy, in this day and age, would anyone want a dual core CPU...
If we are talking about numbers of products sold, dual-cores still easily rule the market by a large margin.
ShurikNMaybe 10 years ago. Today its not enough. A 4 core, as Frick said, should be a basis for everything. Even office work. Besides, MS Office is becoming more and more demanding, nothing extreme, but enough for a 2 core cpu to become a bottleneck. And you never use only word and notepad, there are usually 4+ programs open, couple of tabs in a browser, mail apps, PDFs are getting ridiculously huge and scrolling is choppy on high quality pics... and so on.
I still have yet to see that type of workload overload a decently clocked i3.
Posted on Reply
#35
TheGuruStud
Sihastru"Every core can access every cache with same average latency."

Isn't that like saying that the GTX 970 can access every memory with same average bandwidth? But leaving jokes aside, do they say if a CCX can access the L3 cache of another CCX? If not, I don't see how they can build a true 8 core CPU, but instead a 2P 4 core system with horrible cache latency issues.
Give AMD a lot of money and I'm sure they can do it. Until then, it's not economically viable for them.

Each CCX can access the other L3, but it's over a slower bus, of course. The bandwith/latency hit....who knows how much.
Posted on Reply
#36
FR@NK
TheGuruStudEach CCX can access the other L3, but it's over a slower bus, of course. The bandwith/latency hit....who knows how much.
Its just like this on intel chips, each core as its own L3 cache with a ring bus connecting them all.
Posted on Reply
#37
TheGuruStud
FR@NKIts just like this on intel chips, each core as its own L3 cache with a ring bus connecting them all.
Hopefully, AMD's is as speedy.
Posted on Reply
#38
Captain_Tom
Alexander KaiserIf AMD doesn't have a hot and power hungry architecture on their hands, Zen APUs are going to make for some sick SFF and mobile setups.
That is all I want in my next laptop. A 50w APU that essentially has a mobile i7 + 1024 SP GCN card. You could fit that in a sub-1" thick netbook!
Posted on Reply
#39
Captain_Tom
HD64GFor anyone who request a dual core Zen for office use, just buy A6-A8 with AM4 that will be on sale soon. Or an even cheaper A6 today with cheaper mobo as well compared to AM4 ones. What's the point to go for Zen to use it in office work after all? We are talking about an enthusiast chip, don' t we?
Well we know there will be 6-core Zen's that consist of 4 + 2 modules (The "+2" module is a partially defective CCX). Thus they could make dual cores (4 threads) if they wanted to. The question is if they even need to with APU's taking up the sub $200 space.
Posted on Reply
#40
tabascosauz
ShurikNMaybe 10 years ago. Today its not enough. A 4 core, as Frick said, should be a basis for everything. Even office work. Besides, MS Office is becoming more and more demanding, nothing extreme, but enough for a 2 core cpu to become a bottleneck. And you never use only word and notepad, there are usually 4+ programs open, couple of tabs in a browser, mail apps, PDFs are getting ridiculously huge and scrolling is choppy on high quality pics... and so on.
You are no stranger to SSDs, as is evident from your system specs, so go get yourself an 850 EVO and stop pinning your problems on 2C/4T. I hate the i7 moniker for dual-cores as much as the next guy, but please show some simple regard for concepts such as the thermal envelope in mobile applications, as well as the importance of RAM/[random] storage speed. Every single one of the aforementioned scenarios can be dismissed as more storage-dependent than CPU-dependent. OEMs keep the i7-6700HQ out of laptops that can't handle the heat/power for obvious reasons. Every modern mobile CPU, Intel or AMD, spends its time hovering around sub-GHz speeds so that 1) your battery doesn't need charging after 5 minutes of use and 2) you don't end up with burns on every part of your body that was in contact with the laptop.

I don't buy into the notion that a mobile i7 is the source of your problems, even considering the existence of ULV parts. If a i7-4510U can handle it all with the help of an Intel SSD 530 without chewing through the battery and burning up, so can just about everything else with a -M suffix.


Back on topic: the CCX looks promising for Zen. The whole issue about having to split it up to create APU parts or core counts that aren't multiples of 2 don't seem to be much of a problem; I recall reading about the E5 v4s when they came out and some SKUs looked a little bit irregular and more asymmetric than usual due to the newly increased core counts.
Posted on Reply
#41
xenocide
RejZoRSingle CCX unit CPU could be interesting. That would still be 4 cores, 8 threads. I wonder how would such CPU fare against current generation of AMD's octa cores...
It should absolutely crush them in almost all scenarios. If I remember correctly SMT "cores" are the equivalent of a core running at 80%, so the 40% IPC increase should more than cover the difference.
suraswamiHow confused Windows will be now?
Shouldn't be any issues. They are going with a more traditional processor design than Bulldozer. The only shared component is L3 cache--the reason Bulledozer was all wonky was because part of the main pipeline was shared between "cores".
Posted on Reply
#42
Captain_Tom
xenocideIt should absolutely crush them in almost all scenarios. If I remember correctly SMT "cores" are the equivalent of a core running at 80%, so the 40% IPC increase should more than cover the difference.
I am fully expecting this to be like the launch of the Core series that instantly made their entire previous line-up completely irrelevant.
Posted on Reply
#43
Sihastru
cdawallI'm curious of the same. AMD also has a habit of having slow cache from the get go, which would just make this worse.
From Anandtech's article on this matter:

"The L3 cache is actually a victim cache, taking data from L1 and L2 evictions rather than collecting data from prefetch/demand instructions. Victim caches tend to be less effective than inclusive caches, however Zen counters this by having a sufficiency large L2 to compensate. The use of a victim cache means that it does not have to hold L2 data inside, effectively increasing its potential capacity with less data redundancy.

It is worth noting that a single CCX has 8 MB of cache, and as a result the 8-core Zen being displayed by AMD at the current events involves two CPU Complexes. This affords a total of 16 MB of L3 cache, albeit in two distinct parts. This means that the true LLC for the entire chip is actually DRAM, although AMD states that the two CCXes can communicate with each other through the custom fabric which connects both the complexes, the memory controller, the IO, the PCIe lanes etc."

So... yeah, it doesn't look good.

Note: LLC means Last Level Cache.
Posted on Reply
#44
Caring1
My Processor is that old, it's got a CPU complex :laugh: :nutkick:
Posted on Reply
Add your own comment
Dec 19th, 2024 02:09 EST change timezone

New Forum Posts

Popular Reviews

Controversial News Posts