AMD Instinct MI300X Architecture
Underpinning the MI300X is a CDNA 3 chip as we mentioned.
Here is the MI300 family modular chiplet package. There are XCDs which are the GPU compute dies. The HBM3 memory is pretty standard, but there are eight stacks. AMD also has IO Dies with AMD Infinity Cache underneath the XCDs.
Here is the basics of the XCD. We are not going to re-type what is already on the slide, but this is the basic CDNA 3 accelerator complex.
That new CDNA 3 compute has a number of different numerics. Clearly there was a focus on FP64 compute, but the chip is so big and flexible enough that it can do the FP8, TF32, and more.
Here is the 128 channel interleaved HBM3 memory interface. AMD also has the 256MB of Infinity Cache with 17TB/s of peak bandwidth.
AMD also has to move data from chiplet to chiplet. AMD is showing bandwidth, and it has things like Infinity Cache to hide this a bit, but there is a latency hit whenever traversing the chiplet architecture.
There is a lot here, but let us get to the MI300A and see how the MI300 family can also be an APU. If you are looking for the MI300A architecture discussion like the one for MI300X above, skip a page.
STH testing when?
Great article as always Patrick and Team STH
It looks like a couple of MI300A systems are available: https://www.gigabyte.com/Enterprise/GPU-Server/G383-R80-rev-AAM1 and https://www.amax.com/ai-optimized-solutions/acelemax-dgs-214a/
Couldn’t find prices but if it’s supposed to compete with GH then it’ll be around U$30K.
It’s a good question which of the MI300A or MI300X is going to be more popular. As a GPU could the MI300X be paired with Intel or even IBM Power CPUs?
I personally find the APU more interesting. Not because the design is new so much as the fact that real problems are often solved using a mixture of algorithms some of which work well on GPUs and others better suited to CPUs.
Do you know if mi300A supports CXL memory?
I hope to see some uniprocessor MI300A systems hit the market. As of today only quad and octo.
Maybe a sort of cube form factor, PSU on the bottom, then mobo and gigantic cooler on the top. A SOC compute monster.
In the spirit of all the small Ryzen 7940hs tiny desktops. Just, you know, more.