SK hynix supplies 'early' HBM4 samples, testing will take longer than HBM3E for AI chip makers

SK hynix started supplying its next-gen HBM4 memory in March 2025, but they are "early" versions of its HBM4, with qualification tests expected to take longer than the same tests for HBM3E.

The reason for HBM4 qualification tests taking longer is due to generational changes from HBM3E, where HBM3E memory samples were sent in a nearly complete state. SK hynix sent over HBM3E samples to its clients in August 2023, with mass production starting in March 2024, just 7 months between sample supply and mass production.

HBM4 in its early state will require modifications, with projections that it could take longer than 7 months, with increased technical difficulty with the generational changes cited as a factor that could extend the qualification testing period. The number of I/O terminals for HBM4 has doubled from HBM3E (2048 for HBM4, 1024 for HBM3E). Additionally, HBM4 -- for the first time in this generation -- has the logic die (base die) produced at a foundry (TSMC).

SK hynix will be producing its logic dies using TSMC's advanced process, which will boost data processing speeds and power efficiency. A semiconductor industry official explains: "Since integration and testing must proceed from the early stages, a lot of time will be needed. With HBM4, there are many changes, such as the doubling of IO count, so it won't be easy for Hynix either".

Meanwhile, an SK hynix official explains: "This is not a situation where development has been completed and samples sent, as was the case with HBM3E. Since the generation is changing now, HBM4 is at the level of early sample delivery".