3950x LOW PPD

[BobWilliams757]

You might want to check out this thread...

viewtopic.php?t=35286

He's done a bunch of the testing you are in the process of doing, and you should find similar results. Keep in mind that most of his testing was the A7 cpu core IIRC, and many if not most of the A8 core work has rewarded higher PPD returns. He also test for efficiency in terms of watts/point and has some good suggestions in that aspect.

As for the variations, if you look at HFM and sort by atom counts you will generally find trends. Large cards with lots of shaders and cores usually run fast on higher atom counts. Cards with less shader cores usually run better on smaller atom counts. But even then, you have variations in the length of the simulation, memory speed factors, driver factors, OS factors, and on and on. As such, for any individual system, what the most efficient work units are for that machine will vary. The work units that give low average returns on your system could and often are the ones that "lesser" machines run very well on. I've seen cases where my onboard integrated graphics would approach the PPD return of cards that are much more powerful and capable, but my system is strong with smaller atom counts, and the others start to stretch their legs as atom counts go up.

The above applies more to GPU folding. Though I don't do a lot of CPU folding, I find somewhat the opposite is true even for my little 8 core Ryzen 2400G. If the work unit has an atom count too small, it doesn't load the system as much, nor the memory. So to some extent the larger atom count project usually return more PPD. As with GPU folding there are exceptions to the rule, but the trends are clear. Being your system has 4 times as many cores, much more room for variation in returns.

I think more than likely the larger variations in recent times is due to the larger variations in hardware available to FAH over time, combined with the variations with individual work units and their priority level. The level of priority will dictate that at times the work units might fold on systems other than the optimum, but that ensures the work keeps flowing. If they restrict work units only to machines that are "best" for them, then we have instances where some people aren't getting work to do since their system doesn't fall into the proper capability bracket.

While I am having problems with the GPU (steadily declining from its highs about 12-ish months ago), as you noted, this thread is about AMD CPUs. More specifically, the Zen 2 CPUs (possibly also Zen 3 and beyond).

I have a 3600x (about 3.8-3.9GHz) that is doing about 165K PPD. My 3950x hit a high (so far in my testing) at about 300K PPD at 4.0-4.2GHz before dropping back down. I should be getting, technically, about 2.67 times what the 3600x (6 cores, 12 threads) is doing... BEFORE adding in the higher clock speed of the 3950x. I'm getting less than double right now.

In the distant past (10+ years ago) I've run into problems with Intel compilers (non-enterprise/server versions (40-80 threads per physical CPU)) that stop handling thread counts above what their mainstream CPUs can handle. Since the main stream Intel CPUs (until the 12th generation) maxed out at 8 cores, 16 threads, that kind of matches up with what I'm seeing in my, admittedly, less than perfectly set up testing right now.

I would expect that the compilers for the 12th-plus generation will support more threads, but I doubt that they will EVER maximize AMD Zen CPU performance. I haven't done any programming for a long time and can only hope that newer third-party compilers will continuously improve their AMD optimizations as much as they have for Intel CPUs.

Anyway, back to testing...

Scott

I do understand your concerns, and that was the main reason I posted the link where another folder with the same CPU did testing similar to what you are doing now. Assuming there are no hardware or software issues going on, you should find similar results. Without a close look at HFM logs and/or trends, it's hard to say what it might be beyond work unit variations.

The only thing I can think of that hasn't been mentioned is that not all CPU work units can utilize all cores. If there are no CPU work units that can use the cores you have assigned, it might assign one with a lower core count. If that is the case it generates a warning in the logs something to the likes of "lowered CPUs from 24 to 12" or whatever applies. I don't know if this still takes place, or was a short term thing, as it was mentioned when there weren't many CPU projects in the system.