[mwmalkawi]

Can you please advice is OpenFoam is more of read intensive or write intensive in terms of hard disk specs ?

[flotus1]

For a "typical" simulation, if that even exists, the solver itself should not do much disk I/O at all. During a transient simulation, you probably want to write some results to disk periodically.

[mwmalkawi]

Thank you so i understand a write intensive might be better choice than read intensive?

[flotus1]

Judging by the terminology, I guess you are currently looking at data center SSDs?
read/write intensive is mostly used to distinguish between different drives within a product line. The specification that mostly determines this label is "drive writes per day", along with write performance of course. It is highly unlikely that you will exceed the write endurance of even a read intensive data center SSD, provided you pick one with decent storage capacity.
That being said, I would recommend you look at the actual specifications, instead of a rather vague label. And in case you pick a consumer SSD, maybe have a look at a review to make sure the SSD can handle at least some sustained writes. Which brings me back to my original recommendation: Samsung 970 Evo Plus. You can't go wrong with that.

[B_R_Khan]

Hello!
Can anyone guide how good is Intel Core i9-11900F Processor wth 16M Cache, Up to 5.20GHz speed w.r.t openfoam simulations?

[flotus1]

11900F: not great, not terrible.
It competes with other CPUs that are either slightly cheaper or slightly faster. I7-10700(F/K/KF) or Ryzen 7-5800X. Or even a much cheaper Ryzen 5-5600X, which seems to be enough to saturate the memory subsystem.
The performance difference between these CPUs is smaller than the difference between choosing slow single-rank memory vs. fast dual-rank memory.

[naveedgt]

Originally Posted by flotus1

I would recommend something along those lines: https://geizhals.de/?cat=WL-1604742

You mentioned a budget of around 3000$ in private conversation.
You get a 16-core Epyc CPU with 64GB of RAM. That amount will be enough to run cases with 20M cells.
And I included a relatively large NVMe SSD as an intermediate storage medium for the operating system and the transient simulation results. Add one or more hard drives if you need more storage.
The beauty of this solution: if you ever feel like you need more performance, you can just drop in a second CPU with another 8 DIMMs, and effectively double the performance. Since motherboard prices for single-CPU are not much lower anyway, you would not save a lot of money by restricting your build to one CPU.

Not sure which Ryzen processor you had in mind originally, a 9390x does not exist. If you meant the Ryzen 9 3950x: the Epyc build is several times faster than that for OpenFOAM, even with a single CPU. And also the better choice compared to any Threadripper CPU.

Would you still recommend this or would you update any part of this spec? This seems like a good place to start with upgradeability easily built in.

[flotus1]

With the release of third gen Epyc CPUs a few months ago, this list became outdated.
Motherboard is H12DSi, and CPU(s) are Epyc 7313.
For the graphics card... I have no idea. The market is a mess. Maybe try to get something cheapish on the used market with 4GB of VRAM. That's the threshold where they become useless for the most popular crypto coins.

[B_R_Khan]

Originally Posted by flotus1

11900F: not great, not terrible.
It competes with other CPUs that are either slightly cheaper or slightly faster. I7-10700(F/K/KF) or Ryzen 7-5800X. Or even a much cheaper Ryzen 5-5600X, which seems to be enough to saturate the memory subsystem.
The performance difference between these CPUs is smaller than the difference between choosing slow single-rank memory vs. fast dual-rank memory.

If we compare Xeon with i9, what would you suggest buying for OpenFoam?
Sorry for silly questions as I am not well informed in systems :/

[flotus1]

And that's why I wrote this: General recommendations for CFD hardware [WIP]
It needs some finishing touches, but covers most of the basics for CPUs already.

Labels like "I9" or "Xeon" don't matter a whole lot. Especially the Xeon lineup spans nearly the whole range of CPU classes available these days.