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Comment by zdw | Hacker News Reader

Should be interesting to see how well this works - the primary issue with these APU designs is matching the amount of available memory bandwidth to the CPU and GPU cores.

Assuming they adapt the conventional Ryzen DDR4 controller to be a 128 bit wide GDDR5 controller with a reasonable 7Gbit/s speed, this would have ~120GB/s of memory bandwidth, which is 3x that of the 2400G (which is regarded as bandwidth starved), but slightly more than half what the Intel + Radeon RX Vega i7-8809G has (which is regarded as not having enough GPU cores to use the provided bandwidth).

Probably a reasonably balanced system. Would be interesting to see if this makes it over to their other embedded lines as a high end option: https://www.amd.com/en/products/embedded-ryzen-v1000-series

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I'd guess they use both GDDR5 and DDR4 controllers in the design. AMD is really big on reusing designs (at 80-130 million per mask set for modern manufacture nodes, it's little wonder). Making a profit requires selling at least 10M chips (assuming around $200M masks/R&D and a $20 charge over base cost).

The 2400G is 209mm^2. Doubling the GPU will move that to somewhere around 275-300mm^2 which should place raw chip cost between $35-40 and final chip cost over $60 (probably closer to $80 minimum) with R&D, masks, and profit. But then there's binning. They will get 3 binnings with the target middle being the desired chip.

The extra 15mm^2 for a DDR4 controller would mean they can laser out the GDDR controller and sell it as a 2500/2600G chip or maybe (less likely) make a package that allows both DDR4 and GDDR5. That's a great use for those over/under performing chips.

A huge question here is L3 cache. Will they be adding extra L3 to try to offset the much larger GDDR5 latencies?

8809G doesn't have to share with the CPU. 256 bit controller adapted from Polaris would not go to waste, but you may be right from a cost perspective.

128 bit wide GDDR5 controller with a reasonable 7Gbit/s speed, this would have ~120GB/s of memory bandwidth, which is 3x that of the 2400G (which is regarded as bandwidth starved), but slightly more than half what the Intel + Radeon RX Vega i7-8809G has (which is regarded as not having enough GPU cores to use the provided bandwidth)

Probably a reasonably balanced system

Yes, please! How long before the power and form factor of the Hades Canyon occupies the price point of the PS2? (When the PS2 was current.)

They mention in the article that GDDR5 is embedded "on chip", which presumably means on package.

It does not preclude that the CPU part of an APU can have own regular memory.

>Update 2:

>AMD has updated its press release to state that it is the GDDR5 controller that is on the chip, and not the 8 GB of GDDR5. The memory is installed on the board elsewhere, as with a normal GPU for example.

Also they now have a newer article with photos: https://www.anandtech.com/show/13163/more-details-about-the-...

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