AMD Zen 3 CPUs Deliver New Architecture, Significant IPC Gains & More

AMD Confirms Zen 3 Brings Entirely Brand New CPU Architecture, Delivers Significant IPC Gains, Faster Clocks & Higher Core Counts.

AMD's Senior Vice President, Forrest Norrod, has unveiled some major details of their next-gen Zen 3 CPU architecture in an interview with The Street. According to Forrest, we can expect to see some major performance uplifts with Zen 3 based products, coming from various factors such as new chip architecture and an enhanced process node.

AMD Zen 3 A Bigger Improvement Than Zen 2 Thanks To New CPU Architecture Delivering Higher IPC Gains, Clocks and More Cores
The AMD Zen 3 core architecture will be based on the 7nm+ process node & will be the successor to the Zen 2 core architecture. AMD has already confirmed that the design of the chip has been completed this year which means that launch in 2020 is pretty much set at this stage. Now there are some things we know about the architecture and somethings that we don't. Let's start with what we know about the Zen 3 CPU architecture.

AMD's CTO, Mark Papermaster, revealed back in late 2018 that the 7nm+ node itself would help primarily leveraging efficiency with some modest performance opportunities. AMD's EPYC Milan server lineup is one of the confirmed products to be featuring the new Zen 3 core architecture & AMD has released slides showing how their 7nm+ Milan lineup would offer higher performance per watt compared to Intel's 10nm Xeon lineup aka Ice Lake-SP.

“TSMC may have been measuring a basic device like a ring oscillator — our claims are for a real product,”
“Moore’s Law is slowing down, semiconductor nodes are more expensive, and we’re not getting the frequency lift we used to get,” he said in a talk during the launch, calling the 7-nm migration “
Looking ahead, a 7-nm-plus node using extreme ultraviolet lithography (EUV) will “primarily leverage efficiency with some modest device performance opportunities,”

via EE Times

Now according to TSMC themselves, the 7nm+ process node allows an increase of 20% in overall transistor density while increasing power efficiency by 10%. AMD could take full advantage of the process node and we could see a density boost of up to 20% in the Zen 3 architecture while having 10% better power efficiency.  Some of the details we know for EPYC Milan CPUs include:

• 7nm+ Zen 3 cores (~64 core / 128 thread)
• Pin Compatible With SP3 Socket
• 120W-225W TDP SKUs
• PCIe 4.0 Support
• DDR4 Memory Support
• Launch in 2020

So let's start with things we didn't knew until today. In the interview, Forrest mentions that unlike Zen 2 which was an evolution of the Zen core architecture, Zen 3 would be built completely from the ground up. This would mean that we would be looking at very significant changes with the Zen 3 design unlike Zen 2 which looks and feels familiar but still managed to deliver a solid 15% IPC up-lift which even AMD states were above expectations.

When asked about what kind of performance gain Milan's CPU core microarchitecture, which is known as Zen 3, will deliver relative to the Zen 2 microarchitecture that Rome relies on in terms of instructions processed per CPU clock cycle (IPC), Norrod observed that -- unlike Zen 2, which was more of an evolution of the Zen microarchitecture that powers first-gen Epyc CPUs -- Zen 3 will be based on a completely new architecture.
Norrod did qualify his remarks by pointing out that Zen 2 delivered a bigger IPC gain than what's normal for an evolutionary upgrade -- AMD has said it's about 15% on average -- since it implemented some ideas that AMD originally had for Zen but had to leave on the cutting board. However, he also asserted that Zen 3 will deliver performance gains "right in line with what you would expect from an entirely new architecture."

- The Street

According to AMD, Zen 2 delivered 15% IPC while being an evolutionary design. So going by that, if Zen 3 is an entirely new chip architecture, then we can expect a bigger IPC uplift over Zen 2 with 3. This is also highlighted by the fact that while the 7nm+ process node plays a smaller role in overall performance uplift since the jump from 7nm to 7nm+ won't be as significant as the jump from 14 nm to 7nm, it would deliver moderately higher clock speeds and also better performance per watt which would be a key feature for the new processors, especially against Intel's own 10nm lineup which is also coming out next year in full force.

AMD also confirmed that they will be following Intel's Tick-Tock cadence which Intel seems to have completely abandoned. AMD states that like Intel, a Tick would represent a new process node but similar architecture design as the previous offering while a Tock would represent a brand new chip architecture but with a similar or improved process node. This shows that the Zen 3 architecture will be AMD's first proper Tock since the original Zen core while the existing Zen 2 architecture is a Tick. The Zen+ cores can also be considered a Tock but having a '+', they were more of a mid-term solution that AMD offered with the then brand new 12nm process node.

As for the core count, AMD wants to keep pushing the boundaries with future Zen architectures including Zen 3. Just like Zen 2 doubled the core count of Zen, offering up to 64 cores and 128 threads, Zen 3 would also drive higher core counts with improved nodes. AMD's chiplet design for Zen 2 is one of the most advanced in the industry, offering high core counts at incredibly good performance efficiency.

When asked about a response to Intel's 2.5D and 3D packaging methods which their new Ponte Vecchio Xe GPUs would be utilizing, Forrest mentioned that AMD is also exploring new 2.5DS and 3D packaging approaches for their future chips but didn't mention an exact date as to when we would see those in action.

"There's a number of application areas that just continue to benefit from increasing core counts and increasing compute density," Norrod said. However, he emphasized that AMD also wants to make sure that it takes "a balanced approach" to increase things such as compute density, memory bandwidth, and I/O connectivity so that additional horsepower isn't left "stranded" due to a bottleneck elsewhere.
"You should expect we will continue to drive super hard on packaging technology," he said. Norrod also pointed out that AMD has long used 2.5D packaging to pair memory chips with its GPUs.

- The Street

AMD CPU Roadmap (2018-2020)

Ryzen Family	Ryzen 1000 Series	Ryzen 2000 Series	Ryzen 3000 Series	Ryzen 4000 Series	Ryzen 5000 Series
Architecture	Zen (1)	Zen (1) / Zen+	Zen (2) / Zen+	Zen (3)	Zen (4)
Process Node	14nm	14nm / 12nm	7nm	7nm+	5nm/6nm?
High End Server (SP3)	EPYC 'Naples'	EPYC 'Naples'	EPYC 'Rome'	EPYC 'Milan'	EPYC 'Genoa'
Max Server Cores / Threads	32/64	32/64	64/128	TBD	TBD
High End Desktop (TR4)	Ryzen Threadripper 1000 Series	Ryzen Threadripper 2000 Series	Ryzen Threadripper 3000 Series (Castle Peak)	Ryzen Threadripper 4000 Series	Ryzen Threadripper 5000 Series
Max HEDT Cores / Threads	16/32	32/64	64/128?	TBD	TBD
Mainstream Desktop (AM4)	Ryzen 1000 Series (Summit Ridge)	Ryzen 2000 Series (Pinnacle Ridge)	Ryzen 3000 Series (Matisse)	Ryzen 4000 Series (Vermeer)	Ryzen 5000 Series
Max Mainstream Cores / Threads	8/16	8/16	16/32	TBD	TBD
Budget APU (AM4)	N/A	Ryzen 2000 Series (Raven Ridge)	Ryzen 3000 Series (Picasso 14nm Zen+)	Ryzen 4000 Series (Renior)	Ryzen 5000 Series
Year	2017	2018	2019

As I said, AMD's current chiplet design is pretty advanced on its own and has shaken giants such as Intel in the server and high-end desktop market. They have a strong interconnect fabric known as Infinity Fabric which has been deployed on all of their chips. As of now, AMD is getting very strong demand for their 48 core and 64 core EPYC processors and while there have been reports of 7nm TSMC production being constrained, AMD says that they aren't much of an issue for AMD and they believe that they would absolutely be able to supply whatever the market may demand.

As for the launch itself, AMD's EPYC Milan lineup is scheduled for the end of 2020 but consumer end products would hit the market earlier. AMD's Zen 2 based Ryzen 3000 series processors were introduced in August so based on that, we could see an announcement for the Zen 3 based Ryzen at Computex 2020, followed by a hard launch a few months later. Don't expect the Threadripper parts based on Zen 3 anytime soon since AMD has yet to launch their 3rd Generation Threadripper series in the market with a 64 core part being introduced next year in January.
-wccftech

November 20, 2019