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Comment by lykr0n | Hacker News Reader

I think it would be amazing if there were also able to stick a GB or two of HBM onto the same chip as kind of a L4 cache / VRAM for the GPU. Performance would be amazing, especially considering that Zen's performance gets better with RAM speed and GPUs are almost entirely RAM starved.

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Rumor is that an interposer alone is $20, and HBM is also rather expensive. Basically, you'd easily double the cost of these $99 chips if you put HBM2 onto them... maybe triple the costs if you consider that AMD should charge a margin and actually make a profit from these designs.

After that, the GPU would be too-strong on memory and too weak on compute. The minimum HBM speed 1024-bits / 250GB/s from one stack. Yeah, the same memory-bandwidth as a RX 580 with 2304 shaders, while the APU 2400G only has 704 shaders.

The Intel + AMD chip manages to solve the problem: the CPU, GPU, and HBM2 are all on the interposer. So the expensive interposer has a shared design. Second, the GPU is a fully dedicated Vega design that's roughly the size of an Rx 580. That way, the dedicated-GPU can "keep up" with the super-fast HBM2 RAM.

It's also not using the AMD-style interposer but Intel's EMIB which they claim is much cheaper.

I've never considered that as an idea before, but now am left wondering why it hasn't been done. Guessing the manufacturers make more money from full-unit upgrades than they'd expect to make from incremental memory unit purchases (even if they made the RAM slot proprietary).

Intel has a new chip coming out with AMD graphics and HBM memory: https://www.anandtech.com/show/12220/how-to-make-8th-gen-mor...

But that’s not a desktop CPU. I would gladly buy it if it were.

With a 100W TDP it basically is a desktop CPU.

HBM is fairly new so it is probably a cost issue for the target market.

There was a time where you could put an extra DDR2/3 DIMM on some AMD motherboards to complement their chipset based graphics.

http://www.tomshardware.com/reviews/790gx-graphics-sideport,...

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