Hello you fine Internet folks, here at AMD’s Advancing AI event we are looking at AMD’s brand new Instinct MI455X, replacing the older Instinct MI355X at the top of their AI stack. Instinct MI455X memory subsystem hierarchyThe inter-WGP caches have also changed to support this new design. SoC/Cache ChangesMoving down to the base dies, MI455X has 192 MB of Global L2 cache split across two Fabric Cache Dies (FCDs). Each FCD can deliver up to 27 TB/s of L2 bandwidth, for an aggregate of 54 TB/s across the package. At approximately 7.6 GT/s per pin, those stacks provide a combined 432 GB of HBM4 and 23.3 TB/s of memory bandwidth.