One of my co-workers manages the SGI UV300 described at http://med.stanford.edu/gbsc/uv300.html (new purchased get hardware badged as the HPE MC990 X). It does fit most definitions of a supercomputer, as it's multiple nodes with interconnects that allow a single OS instance to run across all of them (the OS then sees & manages the separate NUMA nodes).

One thing that has been learned is, software will sometimes do interesting things if presented with so much memory. For example: https://github.com/zfsonlinux/zfs/issues/7275

The group I'm in at NASA Goddard has two UV300s. They have 96 cores each (no hyperthreading) and 6TB of RAM. And they are loud.

The SGI Altix line, which used Itanium 2, could go up to 1024 cores with a single system image, which is just insane. We had one of those at Goddard a decade or so ago, but I didn't have access to it.

I'm fairly sure UV (or some SGI labelling) has gone up to 1024-ish cores in a single system image, but I don't have a reference. (SGI Origin 3000 was spec'ed to 512 cores long ago.)

1536 cores on Cambridge’s COSMOS SGI Altix UV2000 system:

http://www.cosmos.damtp.cam.ac.uk

Speaking of SGI, I was expecting the Cray XC family to be able to do that with the ludicrously fast interconnects they have, but I couldn't find any mention of it.

No, an XC40 runs a kernel on each node, the programming model is MPI, not SSI with NUMA. It runs a minimalist Linux distro called CLE. The nodes are surprisingly small, in terms of memory too, 64 or 128G. Physically they are beautiful to look at, so clean, just a CPU and some memory and nothing extraneous. Cray really should do glass cases.

They used to make beautiful computers.

The salient hardware difference is probably cache coherence in the SGI interconnect.

No, the Ares interconnect is brutally fast but it fundamentally isn’t doing anything as complicated as that. It acts as both storage and networking between the nodes.

I missed this at the time, but yes -- that's the point, in comparison with NUMAlink or whatever it is now. (s/Ares/Aries/)

Maybe the HP Enterprise's Superdome line (at least some of the tech is formerly SGI UV series), up to 32 Xeon CPUs / 48 TB RAM? https://www.hpe.com/us/en/servers/superdome.html

Probably very similar to https://www.huawei.com/en/press-events/news/2016/3/Worlds-Fi...

The biggest I heard of was built by SGI (although it was just the husk of SGI which was was bought by another company which kept the name), now HPE. It had up to 32 Xeon sockets (so maybe 256 cores?) and up 24 TB of RAM.