HBM4E is the extended high-bandwidth memory generation after HBM4, designed for AI and other high-performance computing systems. Samsung and SK hynix have announced customer samples with higher reported data rates and larger stack configurations than their HBM4 products. The exact performance depends on vendor and configuration: the announcements do not establish one universal HBM4E speed or bandwidth rating.
What is HBM4E?
HBM4E is a next-generation form of high-bandwidth memory (HBM). SK hynix describes it as an extended product generation following HBM4, aimed at the bandwidth, capacity and power-efficiency demands of next-generation AI systems. It is also relevant to other high-performance computing workloads.
HBM is DRAM built from memory dies stacked vertically and connected using through-silicon vias (TSVs). This arrangement provides a wide, fast connection to a processor. Unlike conventional DDR memory used in general-purpose computers, HBM is designed for integration into computing systems, not as a standard desktop DIMM. See Samsung’s HBM overview and Micron’s HBM explainer.
Two measurements matter when comparing HBM products: capacity, or how much data a stack can hold, and bandwidth, or how quickly it can transfer data. A stack with more capacity does not automatically have a higher bandwidth rating; the figures depend on its design and configuration.
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How is HBM4E different from HBM4?
Manufacturer announcements point to higher per-pin data rates, greater bandwidth claims and higher-capacity stack options for HBM4E. These are vendor-reported specifications and demonstrations, not results from an independent, like-for-like comparison. The following table keeps each figure tied to its source and context.
| Measure | HBM4E claims | HBM4 comparison | How to interpret the figures |
|---|---|---|---|
| Per-pin data rate | SK hynix reports a maximum of 16 Gbps per pin. Samsung reports 14 Gbps stable operation, scalable up to 16 Gbps. | Samsung reports 11.7 Gbps in system-in-package tests and lists speeds up to 13 Gbps on its HBM product page. SK hynix said its HBM4 implementation exceeded 10 Gbps, above the 8 Gbps JEDEC speed cited in its announcement. | These figures reflect different vendor claims and contexts; they are not a single guaranteed rate for every HBM4E stack. SK hynix, Samsung HBM4E sample announcement, Samsung HBM product page and SK hynix HBM4 announcement. |
| Bandwidth per stack | Samsung announced up to 3.6 TB/s for its 12-layer HBM4E sample, then described a 4.0 TB/s HBM4E demonstration at GTC 2026. | Samsung lists up to 3,300 GB/s for HBM4. Micron describes bandwidth above 2.8 TB/s for its 12-high HBM4 example. | The 3.6 TB/s sample claim and 4.0 TB/s demonstration are different Samsung figures and contexts, not one combined product rating. Samsung HBM4E sample announcement, Samsung HBM product page, Micron HBM explainer and Samsung GTC 2026 announcement. |
| Capacity and stack height | SK hynix and Samsung each announced a 48 GB, 12-layer sample. Samsung also says it plans 32 GB 8-layer and 64 GB 16-layer configurations to customer requirements, and its product page describes up to 64 GB in a 16-high stack. | Samsung lists a 36 GB, 12-high HBM4 product; Micron also describes a 36 GB, 12-high HBM4 stack. | A 48 GB 12-layer sample and a 64 GB 16-layer option are different configurations. The 64 GB figure should not be read as the capacity of the 12-layer sample. SK hynix, Samsung HBM4E sample announcement, Samsung HBM product page and Micron HBM explainer. |
| Power efficiency and thermal claims | SK hynix reports over 20% higher power efficiency and 17% improved heat resistance versus its preceding HBM4. Samsung reports 16% improved energy efficiency and more than 14% improved thermal resistance versus its previous generation. | SK hynix reported a power-efficiency improvement above 40% for its HBM4 compared with its prior generation. | Each percentage is a company claim against that company’s stated previous-generation baseline. Different vendors, baselines and methods make these figures unsuitable for a direct head-to-head comparison. SK hynix, Samsung HBM4E sample announcement and SK hynix HBM4 announcement. |
| Implementation | SK hynix identifies Advanced MR-MUF for its 48 GB 12-layer product. Samsung cites 1c DRAM and a 4 nm logic base die. | Samsung also says its HBM4 uses 1c DRAM and a 4 nm logic base die. | These are vendor-specific implementation details, not requirements that define every HBM4E product. SK hynix, Samsung HBM4E sample announcement and Samsung HBM product page. |
How much faster is HBM4E?
There is no single established HBM4E speed to compare with HBM4. SK hynix reports up to 16 Gbps per pin; Samsung reports stable operation at 14 Gbps, scalable up to 16 Gbps. For bandwidth, Samsung announced up to 3.6 TB/s for a 12-layer sample and separately demonstrated 4.0 TB/s at GTC 2026. Those numbers should not be merged or treated as independently verified results.
The HBM4 comparison figures also vary by source and context: Samsung lists up to 3,300 GB/s, while Micron describes more than 2.8 TB/s for a 12-high stack. A fair comparison requires matching vendor, configuration and test context rather than subtracting unlike headline figures.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How much memory can an HBM4E stack hold?
Samsung and SK hynix have each announced a 48 GB HBM4E sample in a 12-layer stack. Samsung says it plans to tailor configurations to customer requirements, including 32 GB in an 8-layer stack and 64 GB in a 16-layer stack. Its product page also describes an HBM4E option of up to 64 GB in a 16-high stack.
For context, Samsung and Micron describe 36 GB capacities for 12-high HBM4 stacks. Comparing 48 GB and 64 GB without noting stack height would obscure an important difference: the 64 GB option uses 16 layers, not the 12 layers of the announced 48 GB samples.
Is HBM4E available yet?
As of October 7, 2026, Samsung and SK hynix have announced shipments of HBM4E samples to major customers. SK hynix dated its announcement June 18, 2026; Samsung says mass production will align with customer schedules after sample shipments and optimization. These announcements establish customer sampling, not general retail availability or a universal mass-production start date.
HBM4E is a component for integration into computing systems rather than a standalone consumer memory upgrade. The manufacturer materials cited here also do not establish a finalized public HBM4E standard or independent, like-for-like testing across vendors. Treat specifications as company-reported claims and demonstrations.
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