High Bandwidth Flash (HBF) by SanDisk: status and timeline

Milestones

Next · HBF first samples delivered

SK Hynix and SanDisk partner on HBF standardizationAug 2025Complete.
HBF consortium formed with Google and TenstorrentFeb 2026Complete.
First HBF standard specification released at FMS 20264 Aug 2026Complete.
First HBF memory die taped out2026Complete.
HBF first samples deliveredTarget Q4 2026Current milestone.
First AI inference product samplesTarget Q1 2027Not yet reached.

Most important updates

SK Hynix and SanDisk release first HBF standard specification at FMS 2026 in Santa Clara4 Aug 2026
SK Hynix and SanDisk partner to standardize High Bandwidth Flash for AI inferenceAug 2025

Upcoming

Q4 2026HBF first samples delivered (next)
Q1 2027First AI inference product samples
Q2 2027First customer inference deployment
Q4 2027Second-generation HBF standard with 1TB+ capacities

Current obstacles

Manufacturing yield at scaleProducing thousands of 512GB HBF modules with high yield requires proven 3D NAND stacking and integration techniques at volume.
System integration complexityCPUs and GPUs must add UCIe HBF support in hardware and firmware. This integration work delays adoption by system makers.
Cost efficiencyHBF must undercut HBM on total cost of ownership while outperforming NVMe. Stacked NAND cost and UCIe controller cost are critical.

Physics limits

NAND flash enduranceFlash cells wear out after millions of write cycles. Inference workloads are read-heavy, but any write activity degrades flash reliability over time.
Bandwidth limits of NAND physicsRaw NAND cells are slow; bandwidth comes from parallel reads across many dies. 3TB/s is near the practical limit without stacking across multiple packages.
Latency versus capacity trade-offLarger capacity stacks increase access time. HBF latency is measurable while HBM latency is microseconds; this impacts inference latency-sensitive models.

How it works

3 parts

Stacked NAND Dies

3D stacking increases capacity density

Multiple NAND die layers stacked in a single package increase total capacity, combining the density benefits of 3D flash with high-bandwidth interface design.

High-Speed Interface

UCIe connects to GPU and CPU

HBF uses Universal Chiplet Interconnect Express to connect to processors at speeds up to 3TB/s, similar to HBM's bandwidth but with far greater capacity.

AI Inference Optimization

Bridges HBM-to-SSD gap for models

Large AI models often have weights that fit in HBF but not in HBM. HBF allows rapid reload of weights during inference without dropping to slow NVMe SSD speeds.

Spec sheet

Spec	High Bandwidth Flash (HBF)
Capacity per stack (first generation)	512 GB^R (reported)
NAND die configuration	8-die or 16-die stacks^R (reported)
Bandwidth - performance grade 1	~0.4 TB/s^R (reported)
Bandwidth - performance grade 3	~3 TB/s^R (reported)
First generation read bandwidth	1.6 TB/s^R (reported)
Capacity advantage over HBM4	8-16x more capacity^E (estimated)

^R reported by the company · ^E our estimate

Update log

2 updates

Tue 4 Aug

Major: SK Hynix and SanDisk release first HBF standard specification at FMS 2026 in Santa ClaraPressHardware

Aug 2025

Major: SK Hynix and SanDisk partner to standardize High Bandwidth Flash for AI inferencePressPartnership

About SanDisk

The team behind High Bandwidth Flash (HBF)

SanDisk

NAND flash storage, High Bandwidth Flash, memory modules

Flash memory company spun from Western Digital Feb 2025. Makes NAND for data centers. Co-leads High Bandwidth Flash standard with SK Hynix.

Spun from WD Feb 2025, trades on Nasdaq as SNDK. Sep 2026 market cap: US$255B.
Co-leads HBF standard with SK Hynix to bridge capacity-speed gap for AI.
HBF samples 2H 2026, production devices early 2027: 512GB at 1.6TB/s.

sandisk.com (opens sandisk.com)Company profile →

Founded: 198838 yrs
Headquarters: United States
Status: Public
Valuation: $255Bmarket capSep 2026
Works in: ComputingPackaging & memory
Coverage: 1 program · 4 updateslatest 4 Aug 2026checked 11 Oct
Partners: SK Hynix (opens skhynix.com)Google (opens google.com)Tenstorrent (opens tenstorrent.com)
Investors: Western Digital (opens wdc.com)
People: David Goeckeler (opens sandisk.com)Chairman and CEOEli Harari (opens en.wikipedia.org)Founder

Spec

High Bandwidth Flash (HBF)

Capacity per stack (first generation)

512 GB^R (reported)

NAND die configuration

8-die or 16-die stacks^R (reported)

Bandwidth - performance grade 1

~0.4 TB/s^R (reported)

Bandwidth - performance grade 3

~3 TB/s^R (reported)

First generation read bandwidth

1.6 TB/s^R (reported)

Capacity advantage over HBM4

8-16x more capacity^E (estimated)