AMD-powered Frontier supercomputer breaks the exascale barrier

Fairly low tech until you get to the super high end.

You have a blend of very specific domain specific knowledge (e.g. they know the hardware - the interconnects more than the CPUs) and old skool Unix system administration.

Although meteorology is in many ways a much older science, I think you are underselling the difference (and importance of computers here). Better computing power means a more accurate forecast, but typically also a longer forecast horizon. That is critical when preparing for natural disasters and absolutely saves lives all the time.

Even at a 3-day lead time, GFS was still suggesting landfall for hurricane Sandy outside the New York region, the longer lead times provided by other centers (with more computing power) were very important for preparation [1].

Even on the science side, increased computing power enables a host of new discoveries. Even storing the locations for all the droplets in a small cloud would require an excessive amount of memory, let alone doing any processing [2]. Increased computer power enables us to better understand how clouds respond to their environment, which is a key uncertainty in predicting climate change.

Many disciplines of meteorology are also much newer than nuclear physics. Cloud physics (for example) only really got started with the advent of weather radar (so the 1940s). Before that, even simple questions (such as can a cloud without any ice in it produce rain?) were unknown.

Even today, we still have difficulty seeing into the most intense storms. You cannot fly an aircraft in there, and radar has difficulty distinguishing different types of particle (ice, liquid, mushy ice, ice with liquid on the surface, snow) and is not good at coutning the number of particles either.

Even after thousands of years, we are onlyjust now getting the tools to understand it. There is a lot left to discover about the weather!

[1] - https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/201...

[2] - https://www.cloudsandclimate.com/blog/clouds_and_climate/#id...

I am still kicking myself every time I look at AMD’s share price. I sold a not-insignificant-to-me amount of shares when the price was basically below 10 a share. Now it’s above 100. All this is to say that the turn around at AMD is good to see and the missteps at Intel are hilarious.

This is like the time the Athlon64 and it’s on die memory controller was kicking the Pentiums around.

You are right that there are problems whose solving speed is limited by the memory bandwidth, and for such problems GPUs may be better than CPUs.

Nevertheless, many of the problems of this kind require more memory than the 8 GB or 16 GB that are available on cheap GPUs, so the CPUs remain better for those.

On the other hand, there are a lot of problems whose time-consuming part can be reduced to multiplications of dense matrices. During the solution of all such problems, the CPUs will reach a large fraction of their maximum computational speed, regardless whether the operands fit in the caches or not (when they do not fit, the operations can be decomposed into sub-operations on cache-sized blocks, and in such algorithms the cache lines are reused enough times so that the time used for transfers does not matter).

The main issue I have with the idea of Navi 21 is that its a 32-wide warp, when CDNA2 (like MX250x) is 64-wide warp.

Granted, RDNA and CDNA still have largely the same assembly language, so its still better than using say... NVidia GPUs. But I have to imagine that the 32-wide vs 64-wide difference is big in some use cases. In particular: low-level programs that use warp-level primitives, like DPP, shared-memory details and such.

I assume the super-computer programmers want a cheap system to have under their desk to prototype code that's similar to the big MI250x system. Vega56/64 is several generations old, while 6800 xt is pretty different architecturally. It seems weird that they'd have to buy MI200 GPUs for this purpose, especially in light of NVidia's strategy (where A2000 nvidia could serve as a close replacement. Maybe not perfect, but closer to the A100 big-daddy than the 6800xt is to the big daddy MI250x).

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EDIT: That being said: this is probably completely moot for my own purposes. I can't afford an MI250x system at all. At best I'd make some kind of hand-built consumer rig for my own personal purposes. So 6800 xt would be all I personally need. VRAM-constraints feel quite real, so the 16GBs of VRAM at that price makes 6800xt a very pragmatic system for personal use and study.