AMD to use HBM1 while NVIDIA goes for HBM2

Hynix is showing off its High Bandwidth Memory (HBM) chips at CeBIT 2015. FUD Zilla was there and received word that the first-generation of HBM will be used in AMD's Fiji (Radeon R9 390X), which is expected to arrive within a couple of months.

NVIDIA on the other hand will adopt HBM with the introduction of its Pascal GPU in 2016 and will use second-generation HBM. This will enable Pascal to have up to 32GB of memory for GPGPU computing tasks, as we wrote yesterday on DV Hardware.

The 4-HI HBM1 has a 1024-bit interface, can handle two prefetch operations per IO and has a maximum bandwidth of 128GB per second. The tRC is 48nm, with tCCD of 2ns (1tCK), and the VDD voltage of 1.2V. For example GDDR5 has 1.35 to 1.5V and a top bandwidth of 28GB/s throughput per chip.

In addition, 4-Hi HBM1 16Gb (2GB per chip) and 8-Hi HBM1 32Gb (8GB per chip) is possible and HBM2 will get double the bandwidth and density. With first generation HBM memory it is at least theoretically possible to design a card with 8GB to 16GB of memory, assuming that the company would be using 4 HBM chips on an interposer, resulting in 512GB/s bandwidth on a four-chip HBM card.

As you can see in the image below, HBM will be much smaller than current GDDR5 and DDR3 memory chips. The first-gen HBM chip you see on the picture has a memory capacity of 1GB, twice as much as the 4Gb GDDR5 and DDR3 chips on the right.



Hynix also showed a wafer with second-generation HBM chips.