SK hynix Ships 12‑Layer HBM4E Samples to AI Customers, Heats Up Battle with Samsung

The race to power the next generation of AI accelerators shifted into a higher gear in June 2026. On June 17, SK hynix officially announced it had shipped samples of its 12‑layer HBM4E (High Bandwidth Memory 4 Extended) to major customers, kicking off the critical customer‑qualification stage . The move came just three weeks after arch‑rival Samsung Electronics began shipping what it called the “industry’s first” HBM4E samples on May 29 . The tight timeline underscores the fierce competition between the two Korean semiconductor titans to dominate the memory behind Nvidia’s upcoming Vera Rubin and other next‑generation AI platforms.

Breaking Down SK hynix’s HBM4E Specifications

SK hynix’s new 12‑layer HBM4E stack delivers a package of improvements purpose‑built to meet the massive bandwidth and efficiency demands of AI training and inference. The company’s own announcement, backed up by industry reports, lays out the following core specs :

• Performance: A data processing speed of up to 16 gigabits per second (Gbps) per pin.
• Capacity: 48 gigabytes (GB) per stack, achieved by stacking 12 layers of 32 gigabit (Gb) die. That 32 Gb single‑die capacity represents a 33% leap in storage density over the previous HBM4 generation .
• Power Efficiency: More than a 20% improvement over the previous HBM4 generation .
• Packaging Technology: The company deployed its proprietary Advanced MR‑MUF (Mass Reflow Molded Underfill) process. A measurable perk is a 17% reduction in heat resistance, which enhances structural stability and thermal management in high‑performance computing environments .
• Bandwidth: While SK hynix said it was targeting a ~4 TB/s class for next‑gen AI chips, its Computex showcase highlighted a 38% bandwidth uplift over HBM4 . Industry reports have also cited a bandwidth of up to 4.0 TB/s .

The chip is fabricated on the 1c DRAM process node, according to an industry report, likely in conjunction with TSMC’s 3‑nanometer process for the base die .

SK hynix vs. Samsung: A HBM4E Specification Showdown

With both companies now sampling their 12‑layer HBM4E products, a head‑to‑head comparison makes the competitive dynamics crystal clear. Samsung was first out of the gate, but SK hynix’s official specs claim an edge in several key performance metrics .

Feature	SK hynix HBM4E	Samsung HBM4E
Sample Shipment Date	June 17–18, 2026	May 29, 2026 (industry first)
Layers	12‑high	12‑high
Capacity	48 GB	48 GB
Per‑Pin Speed	16 Gbps (base)	14 Gbps stable, scalable to 16 Gbps
Energy Efficiency Gain	>20% vs. HBM4	16% vs. HBM4
Packaging	Advanced MR‑MUF (17% lower heat resistance)	Proprietary thermal management (no % improvement given)
Bandwidth	Up to ~4.0 TB/s	Up to 3.6 TB/s per stack

A critical differentiator is base pin speed. SK hynix’s HBM4E runs natively at 16 Gbps, while Samsung’s initial specification is 14 Gbps, with a stated ability to scale to 16 Gbps . Similarly, SK hynix claims a 20‑plus percent power‑efficiency improvement, compared with a 16% gain for Samsung’s HBM4E . And the measurable 17% cut in heat resistance from Advanced MR‑MUF could be a major factor for hyperscale customers packing these modules tightly into AI server racks.

The Larger Battle for AI Memory Dominance

The HBM4E sample shipments are only the latest chapter in a multi‑year struggle to supply Nvidia, the world’s most valuable AI chip designer.

• SK hynix’s HBM4 Stronghold: In late January 2026, multiple sources reported that SK hynix had secured roughly 70% of Nvidia’s HBM4 orders for the Vera Rubin AI platform . That commanding lead over Samsung and Micron was built on early volume production and high yields, especially with MR‑MUF technology .
• Nvidia Confirms All Three: On June 5, 2026, Nvidia CEO Jensen Huang formally certified all three major memory makers—SK hynix, Samsung, and Micron—as HBM4 suppliers for Vera Rubin . The announcement put to rest months of speculation that Micron might be locked out of the platform’s initial supply chain entirely . Industry analysts still estimate SK hynix holds a 60–70% volume share for Vera Rubin’s HBM4, with Samsung capturing 25–30% and Micron filling the remainder .
• A Pattern of Early Sampling: SK hynix established a pattern of aggressive timelines by shipping the world’s first 12‑layer HBM4 samples to customers in March 2025, well ahead of its original schedule . That base HBM4 product is now in mass production and forms the foundation for the HBM4E follow‑on unveiled at Computex 2026 . At the show, SK hynix spotlighted a 33% density increase and 38% bandwidth jump for HBM4E, signaling its roadmap directly to the AI data‑center market .

What Comes Next

With samples now in the hands of major customers—which typically include Nvidia, AMD, and large cloud service providers—the rigorous qualification process is underway . Customers will test the memory for signal integrity, thermal behavior, and compatibility with their accelerator designs. Success at this stage will determine final purchase orders and volume ramps for AI systems expected to debut in the 2027 timeframe.

SK hynix’s ability to deliver its HBM4E samples ahead of its original second‑half 2026 guidance shows it is not merely defending its market lead—it is setting the pace for the entire industry . The fight is no longer just about who can ship first, but whose technology can deliver the most performance‑per‑watt in the most stable package—directly fueling the next quantum leap in AI capability.