AMD 16 core chiplets fly under the radar

[humbug]

Resurrecting this thread.
I was having a look at the potential for having the equivalent of 16 P cores in the nearish future. Intel don't seem to have anything planned.
Some AMD CPUs are "in theory" 16 core, but in use are x2 CCDs of 8 cores, with the CCDs seemingly not talking to each other very effectively, meaning that gaming is apparently worse on a 7950 than a 7800.
I did look at info on the AMD Zen4c, which does look like having 16 cores on a single CCD. However, what I then read was that AMD are doing this by cramming x2 CCX of 8 cores onto a single CCD, with lower cache per core.

Has anyone read of a genuine 16 core (on a single board) in the pipeline?
For that matter, does anyone really understand why many of the synthetic benchmarks can make full use of the 16 cores in current AMD 7950s, whilst most games seem to fail miserably? If so, is there a potential fix?

The problem with 16 P-cores is it would have to be at least 400mm^2, the 13900K is already 260mm^2, that's already huge for a CPU, for context the RTX 4080 is about 380mm^2, the price of something like that would have to be astronomical, its why they have these E-Cores, they are 1/4 the size of the P-Cores, they can cram lots in to keep up with AMD's 16 P-Core CPU's in MT.

AMD's 8 core Zen 5 CCD's are 75mm^2 each, but they are on TSMC 5nm and frankly just far more efficient, even on Intel 10nm they would still be smaller. AMD also use an MCM chiplet design because it further improves the cost effectiveness of the CPU and they can make higher core count CPU's for Data centre than you can monolithic.
Intel have gone down the same MCM rout for its Datacentre CPU's, the Xen 8480+ has 56 core, that's with 4X 14 core chiplets, each one is 480mm^2 (go back to what i said at the beginning) they are very large cores. AMD are at 96 cores, 12X 8 core 75mm^2 chilets

There is no "16 P-Core" chiplet that i know of on AMD's roadmap.

On gaming, what AMD have is an algorithm that keeps the game entirely in one 8 cores CCD, but will allow less latency sensitive workloads on to the seconds CCD if needed, there is a slight penalty in performance when that happens, but it is only slight, i bought a Ryzen 5800X because the gaming performance was more consistent than the 5950X and certainly more consistent than the 5900X, but the difference overall is only a few %.

Intel do the same thing with the E-Core CPU's
Star Citizen is a very good example of a game that uses a lot of threads, all 16 of my threads to be loaded at 80%+ is not unusual, that's with a 2070 Super at 1440P, Intel E-Core CPU's are a problem with this game when running a fast GPU like a 3090Ti or 4080 and up.. the CPU works so hard it is quite often spilling over to the E-Core and because there is a huge performance difference between the E and P-Cores frames are being rendered at very difference performance levels, or speed, with that they stutter in this game, quite badly, Intel have been to CIG to try to sort it out, and its better than it was but its still happening...

Personally i wouldn't buy one, i tend to keep my CPU's for years and games only get more demanding, not less.

 

[Armageus]

Somewhat relevant but Interesting article on core-core latency that I saw earlier:

Core to Core Latency Data on Large Systems

Multicore CPUs have to give user programs a way to synchronize between different cores, and ensure a coherent view of memory. A write from one core has to be made visible to others, even though eac…

chipsandcheese.com

 

[Grim5]

I really want to switch to a massive single ccd CPU with lots of cores and cache but right now AMD is only offering 8 cores and it's such a pain because 8 is fine for just gaming but not fine if you're multitasking

And it doesn't look like Zen 5 will change that. We may not get a 16 core single ccd CPU from AMD until AM6

And while AMD has a 16 core CCD technically working for Zen5C, this chiplet is all little/E cores, there is no 16 core where all cores are P/Big cores and this 16 E/little core chiplet is only going to be used in Laptops, Handhelds etc


A 8 little core, 8 big core zen5c would be nice for a new PlayStation though. Wouldn't want it in my PC but a console can probably be better optimized and use E cores just for background tasks

 

[jigger]

I really want to switch to a massive single ccd CPU with lots of cores and cache but right now AMD is only offering 8 cores and it's such a pain because 8 is fine for just gaming but not fine if you're multitasking

And it doesn't look like Zen 5 will change that. We may not get a 16 core single ccd CPU from AMD until AM6

And while AMD has a 16 core CCD technically working for Zen5C, this chiplet is all little/E cores, there is no 16 core where all cores are P/Big cores and this 16 E/little core chiplet is only going to be used in Laptops, Handhelds etc


A 8 little core, 8 big core zen5c would be nice for a new PlayStation though. Wouldn't want it in my PC but a console can probably be better optimized and use E cores just for background tasks

AMD’s cores are almost identical to each other. AMD’s implementation is very different to Intel’s P+E core scenario as the application just see X number cores and not two different architectures with vastly different hardware resources and topologies.

 

[Mr_Sukebe]

Agreed on the current progress chaps.
In short, whilst AMD and Intel have different approaches, both are currently really only selling 8 core gaming CPUs. All the other stuff are just fripperies.
My belief being that multi-core games are now more prevalent, hence my hope that we'll get 16 and 32 "gaming" CPUs at some point, such that instead of a marginal increase in IPC, that we get a doubling or more of capabilities.

Just a bit frustrated that whilst my 9700 is now fairly old hat, that it probably still has 2/3rds of the gaming performance of one of the latest AMD or Intel CPUs.

 

[BS Dave]

AMD should make a CCD where all the L3 cache is 3D. That way you could have say 12 cores same L1 and 2 cache (maybe more if you wanted) then all the L3 cache on top. That would be a chip

 

[RBImGuy]

Agreed on the current progress chaps.
In short, whilst AMD and Intel have different approaches, both are currently really only selling 8 core gaming CPUs. All the other stuff are just fripperies.
My belief being that multi-core games are now more prevalent, hence my hope that we'll get 16 and 32 "gaming" CPUs at some point, such that instead of a marginal increase in IPC, that we get a doubling or more of capabilities.

Just a bit frustrated that whilst my 9700 is now fairly old hat, that it probably still has 2/3rds of the gaming performance of one of the latest AMD or Intel CPUs.

atm, 6-8 cores are gaming core level
and as far ipc and frequency and cache (x3d) is what elevates gaming
so as long the game devs are unable to utlize design for more cores as usually design goals are based on current and upcoming hardware.
and 16 cores isnt in the design goals for games and unlikely to change in the next 10 years
that is about 3 game cycles only

 

[jigger]

atm, 6-8 cores are gaming core level
and as far ipc and frequency and cache (x3d) is what elevates gaming
so as long the game devs are unable to utlize design for more cores as usually design goals are based on current and upcoming hardware.
and 16 cores isnt in the design goals for games and unlikely to change in the next 10 years
that is about 3 game cycles only

If it takes a decade for games/engines to adopt 16 cores the PC is dead as a gaming platform.

10 years would be 5ish generations at AMD’s cadence or around a doubling of performance excluding the X3D parts, while a 16 core part could offer that same performance gain in a single generation.

 

[RBImGuy]

If it takes a decade for games/engines to adopt 16 cores the PC is dead as a gaming platform.

10 years would be 5ish generations at AMD’s cadence or around a doubling of performance excluding the X3D parts, while a 16 core part could offer that same performance gain in a single generation.

oh the nature of stuff as PC been dead again and again to many but somehow they sell so many still.
a game today 99% of them give or take runs on 1 to 2 cores
scaling a game to more cores to run better is as far how games and engines and devs make games
it means 6 cores to 8 cores are sweet spot and one can make an argument for the 4 core versions but nowadays 6 and 8 are faster ipc and frequency normally and helps with using browsers etc...

while the game runs on mainly 2 cores today for speed boost technology utilizing the rest of cores can then run the game and other things like windows, browser, discord etc..

a game is made with existing hardware in mind as to sell it needs a market.
current specs are console for games first and foremost
Mesh shaders that existed for a while havent been used in games really until alan wake 2.
ray tracing requires resources so the hardware cant run it as its to weak

so a dev have to consider a lot of things as if the game wont sell they cant make more games as they may go bankrupt.
Imagine if you went to work for a game for 3 years then it wont sell due to your built it for hardware that none really uses.
3 years later.....

think about that

 

[jigger]

oh the nature of stuff as PC been dead again and again to many but somehow they sell so many still.
a game today 99% of them give or take runs on 1 to 2 cores
scaling a game to more cores to run better is as far how games and engines and devs make games
it means 6 cores to 8 cores are sweet spot and one can make an argument for the 4 core versions but nowadays 6 and 8 are faster ipc and frequency normally and helps with using browsers etc...

while the game runs on mainly 2 cores today for speed boost technology utilizing the rest of cores can then run the game and other things like windows, browser, discord etc..

a game is made with existing hardware in mind as to sell it needs a market.
current specs are console for games first and foremost
Mesh shaders that existed for a while havent been used in games really until alan wake 2.
ray tracing requires resources so the hardware cant run it as its to weak

so a dev have to consider a lot of things as if the game wont sell they cant make more games as they may go bankrupt.
Imagine if you went to work for a game for 3 years then it wont sell due to your built it for hardware that none really uses.
3 years later.....

think about that

6-8 core desktops have been with use since X58 and AM2+ and consoles moved to 8 cores 10-11 years ago. I was using 18 cores towards the end of 2014 on a desktop-ish system.