Side-by-Side Comparison
Graphics Cards
GDDR6X vs. HBM2
Comparing 2 standards across 7 specifications. 7 key differences identified.
Comparing:
GDDR6X
HBM2
GDDR6X is not a JEDEC standard -- it's a proprietary memory technology Micron developed specifically in collaboration with Nvidia, first shipping in 2020 with the RTX 3080 and RTX 3090. It uses PAM4 signaling, the same two-bit-per-symbol approach PCIe 6.0 later adopted, to reach 19-21 Gbit/s per pin.
HBM2, standardized by JEDEC in January 2016, doubled HBM's maximum stack height to 8 dies and its per-pin transfer rate, reaching up to 256 GB/s of bandwidth per stack and 8GB of capacity per package.
Specification Comparison Table
7 Parameters| Parameter / Spec | ||
|---|---|---|
|
Max Bandwidth / Data Rate
|
19–21 Gbit/s per pin | 256 GB/s per stack |
|
Standard
|
Proprietary (Micron, developed with Nvidia) -- not JEDEC | — |
|
Signaling
|
PAM4 (2 bits per symbol, vs. GDDR5/6's 1-bit NRZ) | — |
|
Introduced
|
2020 (Nvidia RTX 3080 and RTX 3090) | — |
|
JEDEC Standard
|
— | January 2016 (JESD235a) |
|
Max Dies Per Stack
|
— | 8 |
|
Available Capacity Range
|
— | 8GB per package |