AMD ZEN 6 — Next-gen Chiplets & Packaging

Summary

This video script discusses the evolution of AMD's Ryzen CPU generations, highlighting the technological advancements and performance improvements from Zen 2 to the anticipated Zen 6. It delves into the interconnect and packaging design, comparing the simplicity and cost-effectiveness of AMD's current chiplet architecture with the potential benefits and complexities of future technologies like silicon interposers and organic redistribution layers. The script speculates on the likely direction AMD will take with Zen 6, suggesting that an organic interposer with fan-out interconnects, similar to TSMC's InFO_R, could be the most feasible and balanced solution for enhancing bandwidth, reducing latency, and improving energy efficiency across both consumer and server-grade CPUs.

Takeaways

• 🔍 AMD's Ryzen CPUs have seen three generations of Zen architecture with Zen 2, Zen 3, and Zen 4, but the interconnect and packaging design has remained consistent since Zen 2's introduction in 2019.
• 🌐 Zen 2's chiplet architecture used a simple and cost-effective method of connecting chiplets through traces in the PCB, a method that has been in use for decades.
• 🚀 The simplicity of AMD's interconnect technology comes with drawbacks such as low bandwidth, high latency, and higher energy consumption.
• 🔄 Zen 6 is expected to introduce significant changes to layout, packaging, and interconnect design to meet the demands of future Ryzen and EPYC generations.
• 💡 Silicon interposers offer higher bandwidth, lower latency, and better energy efficiency but are complex and expensive to implement.
• 🌉 Silicon bridges, like Intel's EMIB, aim to achieve similar benefits as silicon interposers but with lower complexity and cost.
• 🔗 Organic Redistribution Layers (RDL) with fan-out interconnects, such as TSMC's InFO_R, offer a balance between performance and cost, using organic compounds instead of silicon.
• 🎯 AMD's Infinity Links technology, used in Navi 31 and 32, provides 10x the bandwidth density of Infinity Fabric On-Package with significant power consumption reduction.
• 💻 For desktop Ryzen CPUs, Zen 6's potential shift to Infinity Links could improve latency, benefiting performance in latency-sensitive applications like gaming.
• 🛠️ Server EPYC CPUs could see substantial improvements in interconnect efficiency with Infinity Links, potentially enabling lower TDPs or allowing for more cores and higher clock speeds.

Q & A

What are the Ryzen generations discussed in the transcript?

The Ryzen generations discussed are Zen 2 (Ryzen 5 3600), Zen 3 (Ryzen 5 5600), and Zen 4 (Ryzen 7 7800X3D).

What is the main visual difference between the Ryzen 7 7800X3D and its predecessors?

The main visual difference of the Ryzen 7 7800X3D is the capacitors surrounding it, not the chiplets.

What has remained unchanged in AMD's Ryzen CPUs since the introduction of Zen 2?

The interconnect and packaging design of AMD's Ryzen CPUs has remained unchanged since the introduction of Zen 2.

What significant change is Zen 6 expected to introduce?

Zen 6 is expected to introduce sweeping changes to layout, packaging, and interconnect design.

What are the drawbacks of using PCB for connecting chiplets as mentioned in the script?

The drawbacks include low bandwidth, high latency, and high energy consumption.

What are silicon interposers and their advantages?

Silicon interposers are pieces of silicon placed between the substrate and chiplets, offering higher interconnect density, more bandwidth, lower latency, and reduced energy use.

What is Intel's EMIB and how does it compare to silicon interposers?

Intel's EMIB (Embedded Multi-Die Interconnect Bridge) is a technology that achieves similar benefits to silicon interposers at lower complexity and cost by using smaller pieces of silicon where chiplets meet.

What potential technology might AMD use for Zen 6 according to the transcript?

AMD might use a technology involving organic redistribution layers (RDL) with a fanout interconnect for Zen 6, similar to what is used in Navi 31 & 32.

What are the benefits of using an organic interposer with fan-out interconnects?

Benefits include higher bandwidth, lower latency, and better energy efficiency compared to current Infinity Fabric On-Package.

How might Zen 6 differ in terms of chiplet placement compared to previous generations?

For desktop Ryzen CPUs, Zen 6 might have CPU chiplets placed right next to the IO-die, differing from previous generations where they were located away.