JEDEC, the organization responsible for new standards of micro-electronics, announced an update to the specifications of the second generation of High Bandwidth Memory (HBM2) which will be used by both AMD and NVIDIA in the next generation of graphics cards.

 Specifications of High Bandwidth Memory (HBM2)

HBM2-vs-HBM1

According to JEDEC, the HBM2  memory, will be available with stacks of 2, 4 and 8 levels, this means that the capacity can vary from 1 to 8 GB per cell. According to these new specifications, if AMD or NVIDIA decided to use four stacks in its Polaris or Pascal  graphic card, so we will have a Graphics card with up to 32 GB of memory, although it will be very unlikely to see in consumer grade gaming graphics card, but we could see such capabilities in multiple professional graphics cards.

GPUs and CPUs continue to drive demand for more memory bandwidth and capacity, amid increasing display resolutions and the growth in computing datasets. HBM provides a compelling solution to reduce the IO power and memory footprint for our most demanding applications.

Depending on the configuration taken by the manufacturer, we will have graphics cards with a bandwidth of 256, 512 or 1024 GB / s. In the below graph you can see the performance and capacity of the stacks depending on the number of layers used.

Standard High-Bandwidth-Memory 2
Variant  Layers / Stacks Display Capacity (Layer / Stack / Total) Bandwidth
2-Hi 512 MB 2 / 1 [||] 512 MB / 1 GB / 1 GB 256 GB/s
2-Hi 512 MB 2 / 2 [||]  [||] 512 MB / 1 GB / 2 GB 512 GB/s
2-Hi 512 MB 2 / 4 [||]  [||]  [||]  [||] 512 MB / 1 GB / 4 GB 1024 GB/s
2-Hi 1GB 2 / 1 [||] 1 GB / 2 GB / 2 GB 256 GB/s
2-Hi 1 GB 2 / 2 [||]  [||] 1 GB / 2 GB / 4 GB 512 GB/s
2-Hi 1 GB 2 / 4 [||]  [||]  [||]  [||] 1 GB / 2 GB / 8 GB 1024 GB/s
4-Hi 512 MB 4 / 1 [||||] 512 MB / 2 GB / 2 GB 256 GB/s
4-Hi 512 MB 4 / 2 [||||]  [||||] 512 MB / 2 GB / 4 GB 512 GB/s
4-Hi 512 MB 4 / 4 [||||]  [||||]  [||||]  [||||] 512 MB / 2 GB / 8 GB 1024 GB/s
4-Hi 1 GB 4 / 1 [||||] 1 GB / 4 GB / 4 GB 256 GB/s
4-Hi 1 GB 4 / 2 [||||]  [||||] 1 GB / 4 GB / 8 GB 512 GB/s
4-Hi 1 GB 4 / 4 [||||]  [||||]  [||||]  [||||] 1 GB / 4 GB / 16 GB   1024 GB/s
8-Hi 512 MB 8 / 1 [||||||||] 512 MB / 4 GB / 4 GB 256 GB/s
8-Hi 512 MB 8 / 2 [||||||||]   [||||||||] 512 MB / 4 GB / 8 GB 512 GB/s
8-Hi 512 MB 8 / 4 [||||||||]   [||||||||]  [||||||||]  [||||||||] 512 MB / 4 GB / 16 GB 1024 GB/s
8-Hi 1 GB 8 / 1 [||||||||] 1GB / 8 GB / 8 GB 256 GB/s
8-Hi 1 GB 8 / 2 [||||||||]  [||||||||] 1GB / 8 GB / 16 GB 512 GB/s
8-Hi 1 GB 8 / 4 [||||||||]  [||||||||]  [||||||||]  [||||||||] 1GB / 8 GB / 32 GB 1024 GB/s

DDR3 vs GDDR5 vs HBM1 vs HBM2
DDR3 GDDR5 HBM1 HBM2
I/O 16 32 1024 1024
Prefetch (per I/O) 8 8 2 2
Max. Bandwidth 4.3GB/s
(2133 per pin)
32GB/s
(8Gbps per pin)
128GB/s
(1Gbps per pin)
256GB/s
(2Gbps per pin)
tRC 4x – 5xns 40ns(=1.5V)
48ns(=1.35V)
48ns 45ns
tCCD 4ns (=4tCK) 2ns (=4tCK) 2ns (=1tCK) 2ns (=1tCK)
VPP Internal VPP Internal VPP External VPP External VPP
VDD 1.5V, 1.35V 1.5V, 1.35V 1.2V 1.2V
Command Input Single Command Single Command Dual Command Dual Command

via: Videocardz