Nam Hyun-woo has worked as a staff writer at The Korea Times since 2013, mostly covering business and politics. He currently belongs to the Business Desk where he covers topics such as emerging tech, AI, ICT and Korea's chaebol community. Prior to joining the team, he was the paper's correspondent for the presidential office of Korea during the Yoon Suk Yeol and Moon Jae-in administrations.
SK hynix completes HBM4 development, mass production ready
SK hynix's high-bandwidth memory 4 / Courtesy of SK hynix
By Nam Hyun-woo
Chipmaker takes lead in intensifying race for AI-specific memory
SK hynix has completed the development of high-bandwidth memory 4 (HBM4), a next-generation memory for artificial intelligence (AI) accelerators, which is now ready for mass production, the chipmaker said Friday.
SK hynix is the first chipmaker in the world to complete mass production of HBM4, the sixth generation of the advanced dynamic random access memory (DRAM) variant, which stacks multiple DRAM chips to dramatically boost data processing speeds compared to conventional products.
“The completion of HBM4 development marks a milestone in the semiconductor industry,” SK hynix HBM development head Cho Joo-hwan said.
“By supplying the product that meets customer needs in performance, power efficiency and reliability in a timely manner, SK hynix will fulfill its time to market and maintain a competitive position.”
SK hynix has cemented its status as the world’s most influential memory chipmaker on the back of its dominant supply of HBM3 and HBM3E for Nvidia’s AI accelerators. As demand rises, chipmakers are scrambling to secure an early lead in HBM4. SK hynix has pulled ahead of its rivals by completing development and preparing for mass production, prompting a rosy outlook for its growth momentum.
The company said its HBM4 has the industry’s best data processing speed and power efficiency, with bandwidth doubled through the adoption of 2,048 I/O terminals. This power efficiency represents at least a 40 percent improvement over the previous generation, which the company believes will enhance AI service performance by up to 69 percent in data centers.
The chip’s 10 gigabit-per-second (Gbps) operation speed outperforms the international standard for HBM4 of 8 Gbps, while securing reliability and stability in production by applying advanced mass reflow molded underfill (MR-MUF) process and the 1b nanometer process, which is the fifth finest node dimension in the 10-nanometer class.
“HBM4 marks a symbolic inflection point that transcends the limits of AI infrastructure and will be a key product in addressing the technological challenges of the AI era,” SK hynix AI Infrastructure Division President Kim Ju-seon said.
“We will supply the highest quality and most diverse memory solutions in a timely manner and grow into a full-stack AI memory provider.”
Seen above is Nvidia CEO Jensen Huang's signature on a plaque for SK hynix's memory products displayed at Computex 2025 in Taiwan, May 20. Yonhap
HBM4 is expected to be adopted in Nvidia’s next-generation GPU (graphics processing unit) architecture, Rubin.
Rubin’s technical specifications are expected to be revealed between October and November this year. SK, Samsung Electronics and Micron are currently undergoing Nvidia’s qualification for HBM4, with results expected as early as the end of this year.
Unlike previous generations, HBM4 is produced with different manufacturing processes by each company.
SK hynix is ensuring stability by applying the advanced MR-MUF and 1b process used in its HBM3E. The company was the first to deliver HBM4 samples to customers and became the first to secure mass production readiness, claiming a competitive edge over rivals in qualification processes.
On the other hand, Samsung is seeking to catch up with the 1c process, which is smaller than SK hynix’s 1b, giving them an opportunity to address long-standing concerns over speed and heat specifications on its HBMs and improving their presence.
Meritz Securities analyst Kim Sun-woo estimates that SK hynix will be able to secure an approximately 60 percent market share in 2026, buoyed by its early lead in HBM4.