Today’s regularly scheduled article (part of a series at STH that was set to launch) had to get pulled for re-testing. This has been a busy week where a lot of the editorial team is on PTO so we thought about what could be fun to show. Here is the AMD EPYC 9004 “Genoa” de-lidded so we can see what is underneath the normal heat spreader.
AMD EPYC 9004 Genoa Under-the-Lid
Normally when you see an AMD EPYC 9004 series CPU, it looks something like this.
Around the CPU, there is an orange socket guide and then there is a large metal heat spreader atop the CPU to distribute the heat away from the silicon packages and to the thermal solution.
Here is what that chip looks like without the orange socket guide and heat spreader lid.
In the middle is an AMD EPYC 9004 I/O die. Around that I/O die are twelve CCD packages each with up to 8 cores and associated caches.
The diagram above is the slide version, but if this helps, here is the EPYC chip rotated so the I/O die is oriented as it is in the slide.
That I/O die connects the twelve CCDs, twelve memory channels (and in theory, 2DPC), 128x PCIe Gen5 / CXL 1.1/ Infinity Fabric lanes, and the miscellaneous extra PCIe Gen3 and other lanes onboard.
While looking a the CPU when it has its lid on top may look like a simple hunk of PCB and metal, but underneath the lid, there is a lot more going on.
At the pre-brief event for the AMD EPYC 9004 series, we had a number of photos of de-lidded chips, as we have here. According to Patrick, who was at the event, those photos were apparently removed by someone borrowing the Canon R5 we primarily use for photos (always back up before handing a camera over.) Still, we were able to grab the photos when we took apart a display case:
Hopefully, our readers think this is a fun look at a massive chip. This is also a look at what is to come as multi-chip packages become the norm. In a few years, we will not see a 13-die CPU as an engineering accomplishment. Today, this is one of the most advanced CPUs in the world.