

By Kirt Zimmer, Head of Social Media Marketing, Marvell
Marvell’s business is accelerated infrastructure for the AI era, which is a fast-evolving space that can occasionally confuse even the most earnest student. To help you keep up, we’ve partnered with VentureBeat to explore a multitude of content about that subject:
By Michael Kanellos, Head of Influencer Relations, Marvell
Computer architects have touted the performance and efficiency gains that can be achieved by replacing copper interconnects with optical technology in servers and processors for decades1.
With AI, it’s finally happening.
Marvell earlier this month announced that it will integrate co-packaged optics (CPO) technology into custom AI accelerators to improve the bandwidth, performance and efficiency of the chips powering AI training clusters and inference servers and opening the door to higher-performing scale-up servers.
The foundation of the offering is the Marvell 6.4Tbps 3D SiPho Engine announced in December 2023 and first demonstrated at OFC in March 2024. The 3D SiPho Engine effectively combines hundreds of components—drivers, transimpedance amplifiers, modulators, etc.—into a chiplet that itself becomes part of the XPU.
With CPO, XPUs will connect directly into an optical scale-up network, transmitting data further, faster, and with less energy per bit. LightCounting estimates that shipments of CPO-enabled ports in servers and other equipment will rise from a nominal number of shipments per year today to over 18 million by 20292.
Additionally, the bandwidth provided by CPO lets system architects think big. Instead of populating data centers with conventional servers containing four or eight XPUs, clouds can shift to systems sporting hundreds or even thousands of CPO-enhanced XPUs spread over multiple racks based around novel architectures—innovative meshes, torus networks—that can slash cost, latency and power. If supercomputers became clusters of standard servers in the 2000s, AI is shifting the pendulum back and turning servers into supercomputers again.
“It enables a huge diversity of parallelism schemes that were not possible with a smaller scale-up network domain,” wrote Dylan Patel of SemiAnalysis in a December article.
By Michael Kanellos, Head of Influencer Relations, Marvell
What happened in semis and accelerated infrastructure in 2024? Here is the recap:
1. Custom Controls the Future
Until relatively recently, computing performance was achieved by increasing transistor density à la Moore’s Law. In the future, it will be achieved through innovative design, and many of those innovative design ideas will come to market first—and mostly— through custom processors tailored to use cases, software environments and performance goals thanks to a convergence of unusual and unstoppable forces1 that quietly began years ago.
FB NIC on display at OFC
By Michael Kanellos, Head of Influencer Relations, Marvell
How do you get more data to the processor faster?
That has been the central question for computing architects and chip designers since the dawn of the computer age. And it’s taken on even greater urgency with AI. The greater amount of data a processor can access, the more accurate and nuanced the answers will be from the algorithm. Adding more memory, however, can also add cost, latency, and power.
Marvell has pioneered an architecture for custom high-bandwidth memory (HBM) solutions for AI accelerators (XPUs) and will collaborate with Samsung, Micron and SK hynix to bring tailored memory solutions to market. (See comments from Micron, Samsung, SK hynix and Marvell here in the release.)
Customizing the HBM element of XPUs can, among other benefits, increase the amount of memory inside XPUs by 33%, reduce the power consumed by the memory I/O interfaces by over 70%, and free up to 25% of silicon area to add more compute logic, depending on the XPU design1.
The shift—part of the overall trend toward custom XPUs--will have a fundamental and far-reaching impact on the performance, power consumption and design of XPUs. Invented in 2013, HBM consists of vertical stacks of high-speed DRAM sitting on a chip called the HBM base die that controls the I/O interfaces and manages the system. The base die and DRAM chips are connected by metal bumps.
Vertical stacking has effectively allowed chip designers to increase the amount of memory close to the processor for better performance. A scant few years ago, cutting-edge accelerators contained 80GB of HBM2. Next year, the high-water mark will reach 288GB.
Still, the desire for more memory will continue, putting pressure on designers to economize on space, power and cost. HBM currently can account for 25% of the available real estate inside an XPU and 40% of the total cost3. HBM4, the current cutting-edge standard, features an I/O that consists of 32 64-bit channels - an immense size that is already making some aspects of chip packaging extremely complex.
All About Optimizing XPU TCO
The Marvell custom HBM compute architecture involves optimizing the base HBM die and its interfaces, currently designed around standards from JEDEC, with solutions uniquely designed to dovetail with the design, characteristics and performance objectives of the host AI compute die.
Imagine that a hyperscaler wants an AI inference XPU for edge data centers squeezed into dense business districts or urban corridors. Cost and power consumption will be at a premium while absolute compute performance will likely be less important. A custom HBM solution might involve reducing the size of the AI compute die to economize on chip size and power above other considerations.
At the other end of the spectrum, an HBM subsystem for XPUs powering a massive AI training cluster might be tuned for capacity and high bandwidth. In this situation, the emphasis could be on reducing the size of the I/O interface. Reducing I/O size creates space for more interfaces on the so-called beachfront at the side of a chip and hence, boosting total bandwidth.
The semiconductor market is vastly different than it was a few years ago. Cloud service providers want custom silicon and collaborating with partners on designs. Chiplets and 3D devices, long discussed in the future tense, are a growing sector of the market. Moore’s Law? It’s still alive, but manufacturers and designers are following it by different means than simply shrinking transistors.
And by sheer coincidence, many of the forces propelling these changes happened in the same year: 2006.
The Magic of Scaling Slows.
While Moore’s Law has slowed, it is still alive; semiconductor companies continue to be able to shrink the size of transistors at a somewhat predictable cadence.
The benefits, however, changed. With so-called “Dennard Scaling,” chip designers could increase clock speed, reduce power—or both—with transistor shrinks. In practical terms, it meant that PC makers, phone designers and software developers could plan on a steady stream of hardware advances.
Dennard Scaling effectively stopped in 20061. New technologies for keeping the hamster wheel spinning needed to be found, and fast.