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TOP500 at ISC’26: We have a New Number 1 Supercomputer

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Re: TOP500 at ISC’26: We have a New Number 1 Supercomputer

#61

Post by adrian_b »

jandrewrogers wrote: post #57
adrian_b wrote: post #52

Earlier quoted context omitted.

This seems like a "sour grapes" comment. The new Chinese supercomputer beats all US supercomputers also in HPCG, not only in Linpack. What is remarkable is that this was done despite the US attempts of sabotaging HPC in China by "sanctions". This uses custom CPUs designed in China, which implement an Armv9-A ISA with SME (scalable matrix extension) and which use fast HBM memory. These CPUs are fast enough that they d…

It isn’t “sour grapes”, I remember when the HPC community largely abandoned these benchmarks two decades ago because they weren’t representative of anything real for most of them. The benchmark is a poor reflection of real workloads. There was a long period when the STREAM benchmark was the primary correlate with real-world performance for most HPC workloads but you can’t build a press release from that. I don’t have…

As I have mentioned, and as described in TFA, this supercomputer is also leading in memory bandwidth (4 TB/s per socket => correction, it is 8 Tb/s per socket).

I agree with what you say about benchmarks, but that is precisely why the advantage of this supercomputer over the following American supercomputers will be even greater in more demanding workloads than Linpack and HPCG.

It has already shown this by having an advantage in HPCG of greater than 26% over the fastest US system, while in Linpack its advantage is of only 22%.

Thus its position in the top cannot be dismissed as insignificant, because it more likely underestimates than overestimates this system.

Also the programming effort for writing an efficient program will be lower than for the GPU-based US supercomputers.

Re: TOP500 at ISC’26: We have a New Number 1 Supercomputer

#62

Post by adrian_b »

flopsamjetsam wrote: post #15

> We think it is highly likely that these LX2 chiplets are etched using SMIC 7 nanometer processes at the N+3 refinement, and we base that on the fact that the chip only runs at 1.55 GHz. That is nowhere near the 3 GHz that SMIC can push with that process, but it is probably lower to get the memory and core speeds more balanced. [1] Based on the ARMv9.2. [1] https://www.nextplatform.com/hpc/2026/06/25/a-deep-dive-on-…

Despite what it says at that link, it is more likely to be based on Armv9.3-A ISA, because it supports SME.

In the CPU cores designed by the Arm company, SME has been added only in the latest generation of Armv9.3-A CPUs, which was launched last year.

For each level of Armv9, there are many mandatory features and many optional features.

If the Chinese CPU does not implement all the mandatory Armv9.3-A features (and we do not know anything about this), then it will still be considered only an Armv9.2-A CPU, but even in that case it should be referred as an Armv9.2-A + SME, in order to not confuse it with the Armv9.2-A CPUs that have been used for a few years in smartphones, laptops and mini-PCs and which do not have SME, so they cannot have a comparable performance.

Re: TOP500 at ISC’26: We have a New Number 1 Supercomputer

#63

Post by jandrewrogers »

adrian_b wrote: post #61
jandrewrogers wrote: post #57

Earlier quoted context omitted.

It isn’t “sour grapes”, I remember when the HPC community largely abandoned these benchmarks two decades ago because they weren’t representative of anything real for most of them. The benchmark is a poor reflection of real workloads. There was a long period when the STREAM benchmark was the primary correlate with real-world performance for most HPC workloads but you can’t build a press release from that. I don’t have…

As I have mentioned, and as described in TFA, this supercomputer is also leading in memory bandwidth (4 TB/s per socket => correction, it is 8 Tb/s per socket). I agree with what you say about benchmarks, but that is precisely why the advantage of this supercomputer over the following American supercomputers will be even greater in more demanding workloads than Linpack and HPCG. It has already shown this by having an…

I definitely appreciate the CPU-centric approach. It appeals to my biases and aligns with my technical perspective.

The memory bandwidth is something you can buy. Exotics were >1 TB/s over a decade ago, so 4 TB/s in 2026 is not that impressive. For all practical purposes, these CPUs are also still exotics, you can’t just buy them. I would be very surprised if the memory bandwidth of US exotics haven’t improved over the last 10-15 years.

In any case, for real workloads scalability is mostly a software theory problem at this point and that is still a dark art without much literature.

Re: TOP500 at ISC’26: We have a New Number 1 Supercomputer

#64

Post by adrian_b »

numpad0 wrote: post #59
2OEH8eoCRo0 wrote: post #3

Extremely impressive accomplishment considering they did this with Chinese interconnects and Chinese chips. This is a wake up call.

Not the first time that happened, even for China: https://en.wikipedia.org/wiki/List_of_fastest_computers

This is quite different.

The last time when China had the fastest supercomputer, it was more than 20 times slower than this one and more than 8 times less efficient in energy consumption.

Moreover, its capability was overestimated by the Linpack benchmarks and in other workloads its performance was much less impressive.

For this system, it is the opposite situation. Its result in Top500 underestimates it capability. In other more demanding workloads, where the influence of the memory bandwidth and latency is stronger, its advantage over the US supercomputers is greater than in Top500.

Re: TOP500 at ISC’26: We have a New Number 1 Supercomputer

#65

Post by fragmede »

davidmr wrote: post #26
brianolson wrote: post #7

> Why aren’t these AI companies submitting to the TOP500 to show off their computing prowess? my knowledge is 10+ years out of date, but once upon a time if they'd chosen to, Google could have had _several_ entries in the top 10 of the TOP500 list It's just poker, they didn't want to tip their hand

I’ve worked on several systems that had enough flop/s to make it in the top 5-10, but for which we never submitted benchmarks. Sometimes their backend network layout technically would make them several smaller clusters for an HPL run, sometimes it’s because the cluster is too heterogeneous to get a good benchmark result, and sometimes it’s because the employer wants to keep a low profile. Most of the time, it just th…

What programs were yours running to print money?

Re: TOP500 at ISC’26: We have a New Number 1 Supercomputer

#66

Post by adrian_b »

jandrewrogers wrote: post #63
adrian_b wrote: post #61

Earlier quoted context omitted.

As I have mentioned, and as described in TFA, this supercomputer is also leading in memory bandwidth (4 TB/s per socket => correction, it is 8 Tb/s per socket). I agree with what you say about benchmarks, but that is precisely why the advantage of this supercomputer over the following American supercomputers will be even greater in more demanding workloads than Linpack and HPCG. It has already shown this by having an…

I definitely appreciate the CPU-centric approach. It appeals to my biases and aligns with my technical perspective. The memory bandwidth is something you can buy. Exotics were >1 TB/s over a decade ago, so 4 TB/s in 2026 is not that impressive. For all practical purposes, these CPUs are also still exotics, you can’t just buy them. I would be very surprised if the memory bandwidth of US exotics haven’t improved over t…

Correction, I took the 4 TB/s from TFA, but the NextPlatform article clarifies that it is 4 TB/s per chiplet, but 8 TB/s per socket, so more impressive.

The only US-designed CPU "exotics" are the Intel Xeon Max CPU series, which use HBM like the Chinese CPUs, but which have a theoretical maximum throughput of only 1.6 TB/s per socket, i.e. 5 times slower than the new Chinese CPUs.

Moreover, the users of Intel Xeon Max complained that they cannot reach the theoretical memory bandwidth. I do not know if that was due to some bug that might have been solved later by Intel with a microcode update or a new mask set stepping.

The server CPUs with standard DIMMs, which will be launched by AMD and Intel next year, will have a memory bandwidth of around 1 TB/s per socket.

The AMD MI300 GPU used in the fastest US supercomputer has a memory throughput of 5.2 TB/s per socket, so lower than the 8 TB/s per socket of the Chinese CPU, which explains why the advantage of the Chinese system increases in the benchmarks more dependent on memory performance.

The latest AMD Instinct GPU, MI355X, increases the memory bandwidth to 8 TB/s, so equal to the Chinese CPU.

However, it may pass some time until someone will build such a big system with MI355X, though perhaps the existence of this new contender might prompt the US labs to upgrade their systems by replacing the older AMD GPUs with newer AMD GPUs.

Re: TOP500 at ISC’26: We have a New Number 1 Supercomputer

#67

Post by wanderingmind »

brianolson wrote: post #7

> Why aren’t these AI companies submitting to the TOP500 to show off their computing prowess? my knowledge is 10+ years out of date, but once upon a time if they'd chosen to, Google could have had _several_ entries in the top 10 of the TOP500 list It's just poker, they didn't want to tip their hand

My sense is you only submit if you are in the business of selling supercomputing cluster (IBM, Cray). If you are a consumer or build to consume internally, you would care less.

Re: TOP500 at ISC’26: We have a New Number 1 Supercomputer

#69

Post by microgpt »

antonvs wrote: post #40
amelius wrote: post #33

Earlier quoted context omitted.

GPUs are for graphics (the G in GPU). These systems are used for more general computations.

GPUs were for graphics. Now, they're mainly used for machine learning training and inference. The big tech companies are spending eye-watering amounts for GPUs - hundreds of billions of dollars a year each. That's the reason that Nvidia's market cap is at $4.66 trillion.

In between those, they were for Ethereum mining.

Re: TOP500 at ISC’26: We have a New Number 1 Supercomputer

#70

Post by numpad0 »

adrian_b wrote: post #64
numpad0 wrote: post #59

Earlier quoted context omitted.

Not the first time that happened, even for China: https://en.wikipedia.org/wiki/List_of_fastest_computers

This is quite different. The last time when China had the fastest supercomputer, it was more than 20 times slower than this one and more than 8 times less efficient in energy consumption. Moreover, its capability was overestimated by the Linpack benchmarks and in other workloads its performance was much less impressive. For this system, it is the opposite situation. Its result in Top500 underestimates it capability.…

It's the same. Nobody was buying POWER9 or A64FX systems, and manufacturers of those are no factor to anything.

One could theoretically drive home with a ready-to-go rack of non-American and/or non-x86 supercomputer nodes at any point in time across the last few decades, sometimes even with non-NVIDIA/AMD massively parallel coprocessor cards. Nobody did.

If China(or any country) would _ship_ these alternative supercomputer hardware, only then anything could change.

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