18 months later, MediaTek dominates the SoC landscape in China and many other markets, with two generations of its octa-core parts.
MT6797 packs two A72 and eight A53 cores
The unannounced MT6797, leaked in slides published by Chinese tech sites, takes the multi-core approach to a new level. The chip uses what MediaTek describes as a “huge.Medium.TINY” design, which means it has three CPU clusters.
The huge cluster uses two Cortex-A72 cores clocked at 2.5GHz for “eXtreme Performance” (the same moniker used in X-series Helios parts). The huge cluster is backed by a squad of Cortex-A53 cores in two quad-core clusters. The Medium cluster is clocked at up to 2.0GHz and provides the best performance/power balance, while the TINY cluster ends up clocked at 1.4GHz and delivers the best power efficiency.
MediaTek used an automotive analogy to describe how it all works, comparing its three CPU clusters to three gears on a car.
All three clusters have their own L2 cache, they are connected to MediaTek’s Coherence System Interconnect (MCSI) and a 128-bit AXi memory bus.
No word on GPU yet
This unique approach should enable MediaTek to make the most of different core clusters, but a lot of questions remain unanswered.
Previous leaks suggested the new chip would be manufactured on TSMC’s 20nm node. While this may sound like an inadequate node for a deca-core chip, bear in mind that each cluster of A53 cores should end up smaller than a single Cortex-A57 or Cortex-A72 core. In other words, it should be easy to pull off since we already have quad-core Cortex-A57 parts with four additional A53 cores on the same node.
Another big piece of the puzzle is missing – there is no word on the GPU. We can only speculate on what sort of GPU MediaTek is using. The company employs ARM Mali and Imagination Technologies GPUs on its smartphone SoCs, but a mystery GPU has been spotted on an unrelated tablet SoC. This could be an AMD or Nvidia design for all we know, but it’s impossible to say with any degree of certainty.
Early benchmarks suggest the MT6797, or MediaTek Helio X20, should break the 70,000 barrier in Antutu, making it a very competitive part, provided it launches this year. This is another big question – when will this part start shipping? MediaTek’s Helio X10 is just out of the gates and, according to previous reports, the company is not planning to move to 20nm before Q4 2015.
