Nvidia Tapped To Accelerate RIKEN’s FugakuNext Supercomputer

[u/NamelessVegetable]

https://www.nextplatform.com/2025/08/22/nvidia-tapped-to-accelerate-rikens-fugakunext-supercomputer/

[u/NamelessVegetable]

This marks the end of Japan exclusively using Japanese technology for its flagship supercomputers. I cannot stress how significant a shift this is. Japan's been designing their own supercomputers since the late 1970s. The tremendous investment that GPUs have received from AI has finally forced Japan to concede and join the herd in adopting them.

[u/acideater → u/NamelessVegetable]

I don't think that has been the case since the 80's if not further back. What does using exclusive Japanese tech mean? Using their own foundry, chip design, software and memory? I don't think that has ever been the case.

The Japanese will always employ some Japanese companies for its government contract, but the foundation of the supercomputer always relied on a multitude of companies and tech and has for decades.

Its kind of silly to use exclusive tech and put yourself at an immediate disadvantage. Your really not going to overcome Nvidia GPU's. I imagine you'd want your super computer to do AI capable workloads so you sort of have to go with Nvidia.

[u/NamelessVegetable → u/acideater]

I was referring to Japan's flagship supercomputers. Of course Japan uses non-Japanese supercomputer technologies. That was the case even back in the 1980s, when the first Japanese supercomputers appeared. Crays co-existed alongside vector supercomputers from Fujitsu, Hitachi, and NEC.

A more recent example would be their AI Bridging Cloud Infrastructure (ABCI) supercomputer, which adopted NVIDIA GPUs at around the same time as everyone else did. But it wasn't one of their flagship supercomputers; the contemporary flagship supercomputer to the first-generation ABCI would have been the Fujitsu K computer, which used SPARC64fx VIII processors.

Japan has been building a flagship supercomputer once a decade ever since the Earth Simulator from 2004. All of their flagship supercomputers from the 1990s till present have been Japanese:

• Numerical Wind Tunnel (1993) was distributed memory system built from Fujitsu vector processors and crossbar switches.
• CP-PACS (1996) was a built from Hitachi-designed PA-RISC microprocessors and crossbar switches.
• Earth Simulator (2004) was built from NEC-designed vector processors, custom DRAMs, and crossbar switches.
• K (2012) was built from Fujitsu SPARC64fx VIII processors; the interconnect was Fujitsu's Tofu.
• Fugaku (2020/2021) was built from Futjisu A64fx processors; the interconnect was Fujitsu's Tofu-D.

I've left out a few significant systems, like the Fujitsu FX1 from the late 2000s, which was a smaller system for JAXA that didn't appear in the top 10 of the TOP500 list, but which was an important (in the context of Japan) precursor to the K computer. I think there was also a large Hitachi SR8000 installation c. 2000 that was based on heavily customized 64-bit PowerPC processors designed by Hitachi. Those processors weren't merchant silicon.

I don't think that has been the case since the 80's if not further back. What does using exclusive Japanese tech mean? Using their own foundry, chip design, software and memory? I don't think that has ever been the case.

Actually, the Japanese vector supercomputers of the 1980s and 1990s, up until the NEC Earth Simulator/SX-6 were exclusively Japanese by your definition (my definition is being responsible for the processor and system design). Fujitsu, Hitachi, and NEC designed the architecture, processors, memory (DRAM or SRAM), peripherals (mostly storage), and operated the fabs (these companies vertically integrated conglomerates that were among the largest semiconductor companies in the world during that time); and they developed the OS and application libraries as well.

Its kind of silly to use exclusive tech and put yourself at an immediate disadvantage. Your really not going to overcome Nvidia GPU's. I imagine you'd want your super computer to do AI capable workloads so you sort of have to go with Nvidia.

The silliness you speak of is exactly what Japan did by forcing Fujitsu to invest over a billion dollars to build a 45 nm fab so they could claim that the SPARC64fx VIII processors in the K computer were Japanese made. That fab was pretty much obsolete the moment it opened, and is now owned by UMC.

[u/zdy132 → u/NamelessVegetable]

Very interesting read. I had no idea Japan was still manufacturing high performance chips as recent as 2021, let alone on a 45 nm node, when TSMC was already pumping out Apple's A14 chip at 5 nm.

I can see why the Japanese government wanted that, but still, building a 45 nm node fab at the age of 5 nm was quite a decision.

[u/NamelessVegetable → u/zdy132]

The 45 nm fab was for the K computer, which was Fugaku's predecessor from ~2012. So it wasn't 45 nm versus 5 nm, but 45 nm versus Intel's 22 nm Tri-Gate finFET and TSMC's 28 nm bulk, which IIRC, were the leading nodes back then. Not quite as extreme a difference, but still, 45 nm bulk in 2012 was still not a very good idea for the sake of national pride. I believe a senior person involved in the K computer recently admitted as much.

[u/zdy132 → u/NamelessVegetable]

Thanks for the clarification.

It's a shame that Japan can not manufacture top tier nodes now. The world can really use some competitors against TSMC. Hopefully Rapidus can see some success, and by extension lower the top tier chip prices for us.

[u/opticalsensor12 → u/NamelessVegetable]

Is Tofu D the same thing as UCIe? A die to die interconnect?

[u/NamelessVegetable → u/opticalsensor12]

It's not. The A64fx processors in Fugaku are monolithic dies; they're not based on chiplets as you might expect from a high-end processor from the late 2010s. Tofu-D, however, is largely implemented on the same die as the processor, and its network interfaces are linked directly to the NoC that connects the processor cores, HBM memory controllers, PCIe interfaces together.

And because Tofu-D has a 6D torus topology, the routers are much smaller than those of other supercomputer interconnect networks like Cray's Slingshot (as used in El Capitan), Fujitsu placed the router on the processor die too. So Tofu-D is die-to-die only in the sense that the A64fx processor dies are linked to each other. The optical PHYs are external though, but I'm not sure where the electrical PHYs are (Tofu-D uses optical links for links going out of the rack and electrical ones for connecting to other processors within a rack).

This is more integrated than other interconnects like Slingshot, which IIRC, has external NICs (either as a separate ASICs on the system board, or expansion cards, IIRC) that are connected to the processors via PCIe links. The Tofu series of interconnects were a major reason why Fujitsu supercomputers performed as well as they did.

[u/xternocleidomastoide → u/NamelessVegetable]

Japan has used plenty of non-Japanese supercomputer tech before.

Some of the largest systems in Japan were using x86 and POWER CPUs, Cray has sold a lot of units there as well. This is not even the first time they deploy huge GPU clusters using NVIDIA stuff either.

[u/NamelessVegetable → u/xternocleidomastoide]

Japan has used plenty of non-Japanese supercomputer tech before.

I never claimed that they didn't. I only said they did for their flagship supercomputers.

Some of the largest systems in Japan were using x86 and POWER CPUs, Cray has sold a lot of units there as well.

The Hitachi SR12000/14000/16000/18000 (was there a 10000? I dunno...) never had very large installations AFAIK, apart from those that they sold of Japan's meteorological agency, which were sort of middle-sized at best.

This is not even the first time they deploy huge GPU clusters using NVIDIA stuff either.

If you're referring to the first ABCI system, that was not funded at the same level as K, Fugaku, or FugakuNext. The first generation was faster than the K computer though, because it was a ~year newer, and the K was delayed from ~2010 to ~2012.

[u/xternocleidomastoide → u/NamelessVegetable]

Again. Japan has had several "flagship" supercomputers that used non Japanese technologies in the past couple decades.

Even in the 80s/90s Japan was one of the biggest market for American supercomputer vendors (Cray et al)

[u/NamelessVegetable → u/xternocleidomastoide]

Again. Japan has had several "flagship" supercomputers that used non Japanese technologies in the past couple decades.

Which ones would these be? I'm genuinely curious. Does your use of the word "flagship" imply that they have appeared at the top of the TOP500 list, as the ones I listed in another comment in this thread have, and have received a comparable level of political support from the Japanese government?

[u/xternocleidomastoide → u/NamelessVegetable]

Yes. 2 of the top 3 Japanese Supers in the Top500 are Xeon/NVDA clusters .

Most Japanese entries in the Top500 use INTL/AMD/NVDA cpus/gpus.

[u/NamelessVegetable → u/xternocleidomastoide]

I assume that the systems you're referring to are ABCI 3.0 and CHIE-3 from the 2025-06 edition? These are not flagship systems, in the sense that they are the most powerful system(s) a country has. They're powerful, useful systems, no doubt, but ABCI 3.0 only has ~one third of the peak and attained FP64 performance of Fugaku, despite being built four to five years after it. CHIE-3 is around one quarter of Fugaku's performance. These systems have never been in the top 10. Their scale (in terms of physical volume) also doesn't compare; Fugaku is simply more massive.

If one looks at the US' trio of flagship systems, El Capitan, Frontier, and Aurora, their peaks are 2.75, 2.06, and 1.98 EFLOPS, respectively. El Capitan has ~0.7 PFLOPS more peak than the others, but you can surely appreciate that these systems are in the same class; whereas Fugaku is far ahead of ABCI 3.0 and CHIE-3.

[u/xternocleidomastoide → u/NamelessVegetable]

k LOL.

[u/donutloop]

Quote from article: "FugakuNEXT answers that call, drawing on NVIDIA’s whole software stack —  from NVIDIA CUDA-X libraries such as NVIDIA cuQuantum for quantum simulation, RAPIDS for data science, NVIDIA TensorRT for high-performance inference and NVIDIA NeMo for large language model development, to other domain-specific software development kits tailored for science and industry."

https://developer.nvidia.com/cuquantum-sdk

https://blogs.nvidia.com/blog/fugakunext/

[u/Professional-Tear996]

This is only for the GPU part. The software libraries that will run on the CPU is using parts of Intel's OneAPI and various DL libraries and MKL - being ported over to Arm, and the CPU in it will be the successor to the A64FX, dubbed Monaka.

[u/From-UoM → u/Professional-Tear996]

They are going to be using almost all of Nvidia's software

FugakuNEXT answers that call, drawing on NVIDIA’s whole software stack — from NVIDIA CUDA-X libraries such as NVIDIA cuQuantum for quantum simulation, RAPIDS for data science, NVIDIA TensorRT for high-performance inference and NVIDIA NeMo for large language model development, to other domain-specific software development kits tailored for science and industry.

https://blogs.nvidia.com/blog/fugakunext/

[u/Professional-Tear996 → u/From-UoM]

That is for the GPU.

[u/hwgod → u/Professional-Tear996]

The software libraries that will run on the CPU is using parts of Intel's OneAPI and various DL libraries and MKL

Source?

[u/Professional-Tear996 → u/hwgod]

Just go to Fujitsu's website and look at the materials for Monaka.

[u/hwgod → u/Professional-Tear996]

Then link it if it's so easy. Not going on your wild goose chase for something you more than likely lied about.

[u/WarEagleGo]

A future GPU from Nvidia will be doing nearly all of the numerical heavy lifting in the FukaguNext system, which is expected to be operational in 2030.

[u/Zwift_PowerMouse]

Japan has never hesitated to ‘borrow’ ideas and technology. Often they take it, break it, and make it back better.

[u/NamelessVegetable → u/Zwift_PowerMouse]

I really hope you're not invoking that old, tired trope where Japan doesn't innovate and just copies other people's (read American) technology. Their approach to supercomputer design has been intelligent and original if one bothers to examine it more closely. They've largely predicted and adjusted to technological trends correctly. Some historical examples from the 1990s would be going with CMOS instead of sticking with BTs, using DRAM instead of SRAM, and going with distributed memory for greater scaling of processor counts and memory. Contemporaneously, Cray would largely resist every single one of these developments.

[u/xternocleidomastoide → u/Zwift_PowerMouse]

So like, everybody else then.

[u/Zwift_PowerMouse → u/xternocleidomastoide]

Yes. Especially the USA.

[u/Wiggy-McShades77 → u/Zwift_PowerMouse]

Isn't that how all human innovation works?