By Dr. Phil Garrou, Contributing Editor

AMD announces HBM in 2015 High End Graphics Module “FIJI”

For over two years now, IFTLE has been saying that memory stacks will soon be seen in high end graphics processor modules. Nvidia was the first to announce the use of stacked memory with GPUs [see IFTLE 145 “GPU Roadmap….” (April 2013)]. Nvidia’s Volta GPU module was scheduled for 2015 release and was supposed to use the Micron Hybrid Memory Cube (HMC). Rumors are that after HMC’s development fell behind the proposed roadmap timing, Nvidia moved the Volta introduction out to > 2016 after the Pascal module, which will be based on Hynix HBM 2 and is scheduled to be commercial in 2016.

So now the first commercial graphics products to feature HBM clearly will be AMD’s R9 390X series Fiji GPU in 2015. The Rx 300 series will also reportedly be the first to feature TSMC’s 20nm technology and the first to be equipped with HBM. There are 4 HBM stacks packed on the same interposer as Fiji. Each HBM stack has a capacity of 1GB of memory.

Recent rumors from Taiwan indicate that production is being slowed by issues concerning delivery of the silicon interposers from their primary supplier. Reports are that AMD is having to rely more heavily on the secondary supplier to try to keep production on track.

The first generation of HBM promises to deliver 4.5X the bandwidth of GDDR5 and 16X the bandwidth of DDR3 as shown below.

The second generation HBM is well underway and promises to double the bandwidth by doubling the speed from 1Gbps to 2Gbps. It will also quadruple the memory capacity for 4-Hi stacks from 1GB to 4GB.

Reportedly HBM2 is scheduled to be featured in AMD’s upcoming “Greenland” GPU [link]. It’s rumored that the new graphics family will be manufactured at Globalfoundries on their 14nm FinFET process node which would be a major loss for TSMC.

A summary of AMD graphics processor modules is shown below.

There are also reports that AMD is working on multicore APUs that will use similar interposer / HBM memory technology [link].

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