AMD Instinct MI300 ‘GFX940’ GPU, Next-Gen Data Center MCM Accelerator, Makes Possible First Appearance In Linux Patch
The latest Linux Patch has included a new target for an unreleased AMD ‘GFX940’ GP which has a similar ISA as the Aldebaran ‘GFX90a’ GPU. It is speculated that this chip could be powering AMD’s next-generation Instinct MI300 GPU accelerator and supports all the data-centric features such as MFMA (Matrix-Fused-Multiply-Add), full-rate FP64, and packed FP32 operations. Other features also include XNACK which is specific to CPU+GPU memory space integration, as Coelacanth-Dream puts it. The source states that although the GPU ISA is similar, the GFX940 does have a few differences when compared to Aldebaran ‘CDNA 2’ GPUs which are listed below: Previous rumors have indicated that the AMD Instinct MI300 will feature a 4-GCD design based on the brand new CDNA 3 architecture. The upcoming Instinct MI200 was going to feature 128 compute units per die but that has changed to 110 compute units since last week’s rumor. A total of 220 Compute Units would net 14,080 cores and if we take the exact number and multiply it by 4 (the number of GCDs on Instinct MI300), we end up with 440 Compute Units or an insane 28,160 cores.
— Kepler (@Kepler_L2) March 1, 2022
— Kepler (@Kepler_L2) September 7, 2021 A recent AMD ROCm Developer Tools update that was spotted by Komachi did confirm a maximum of 4 MCM GPUs but those are simply ‘Aldebaran’ SKUs. There are expected to be at least four CDNA 2 powered Instinct accelerators with their respective (unique IDs) listed below. Note that the number doesn’t represent the number of dies on each device but rather the device itself:
0x7408 0x740C 0x740F 0x7410
Now that would be true if AMD makes no changes whatsoever when moving from CDNA 2 to CDNA 3 but that’s not the case. CDNA 3 is expected to bring forward a revised new architecture that won’t be another Vega derivative like Arcturus or Aldebaran which makes this rumor more believable. The GPU architecture may also use a layout that might end up looking similar to the new WGP/SE arrangement on the new RDNA 3 chips or an entirely new design tailored towards the HPC segment. But one thing is for sure, those quad-MCM GPUs definitely are something that we can’t wait to see in action!
AMD Radeon Instinct Accelerators 2020
