[Chief Cookie]

Brief:
This will be a single workstation and not part of a cluster.

I will be using it mainly for fire modelling using FDS software. Although will use it for video editing/rendering and CAD.

Technical requirements of software:

"The single computer or compute cluster ought to have fast processors (CPUs), and at least 2 to 4 GB RAM per core. The CPU speed will determine how long the computation will take to finish, while the amount of RAM will determine how many mesh cells can be held in memory.

For the purpose of running FDS on a Windows computer, the number of logical processors is your most important consideration.

Parallel Processing FDS employs OpenMP, a programming interface that exploits multiple processing units on a single computer.

FDS will use approximately half of the available cores on a single computer. This is done for two reasons: (1) so as not to take over your entire machine when you run a simulation, and (2) because using all cores for a single simulation may not minimize the run time OpenMP works best when exploiting multiple (logical) cores associated with a single (physical) processor or “socket”

FDS handles parallelism at the mesh level. "

Second from software that uses FDS as a base:
"A fast CPU. In our experience, it's better to get a processor with high clock speeds per core rather than lots of cores. We like to use Intel i7s in our office."
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Proposal:
1. 3rd gen threadripper 3970x with 32 cores at 3.7 Ghz with corsair 64gb dominator DDR43600.
2. 2x EPYC Rome 7402 24 core 2.8 Ghz- 64gb+ ram.
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Questions:
Which should I go for based on tech spec?

I am conscious that option 1 has approx. 1ghz over option 2 in terms of speed but option 2 will have 8 memory channels as opposed to 4. I will also be overclocking option 1, both CPU and RAM.
Concerns with option 1: the RAM isn’t registered, not sure if that is a problem
Concerns with option 2: what’s the best ram I can use? Not sure how much overclocking Rome will support either.

Any suggestions?

thanks

[ashokac7]

I would give simple advice. Get server CPU for server load. sometimes simulations runs for long time, so server based CPU would get an advantage.
Also I don't think overclocking is very good options for running a parallel job. It will depend on the fact that how each core gets overclocked. If one is faster than other, it will stall for other to catch up.

Again Intel i7 may be good for PC, this is good for single therad load, but for parallel load, it will run hot and more thread gets an edge.

Epyc also support infinity fabric. Infinity fabric enables faster communication between cores for better parallel computing. You may want to look into this first. Just formulate the bottlenecks in your job. Larger jobs will be benefited from more bandwidth (Epyc) , 8 channel RAM and more L3 cache.

So CPU overclock may be the last thing to look for.

These are just my suggestion. I am also an amateur in this. So refer some valid proofs before making a decision.

[flotus1]

FDS will use approximately half of the available cores on a single computer. This is done for two reasons: (1) so as not to take over your entire machine when you run a simulation, and (2) because using all cores for a single simulation may not minimize the run time OpenMP works best when exploiting multiple (logical) cores associated with a single (physical) processor or “socket”

My best attempt at translating this into normal CS terminology: "Our OpenMP code is not NUMA-aware"

So if we are going by the sections you quoted from their documentation, your best bet should be a single Epyc Rome CPU. For example Epyc 7402P.
Pair it with 8 DIMMs of DDR4-3200 reg ECC.

To answer the rest of your questions:

Concerns with option 1: the RAM isn’t registered, not sure if that is a problem

Registered memory is one way to get higher total capacity. If you get the memory capacity you need without RDIMM, there is no problem.

Concerns with option 2: what’s the best ram I can use? Not sure how much overclocking Rome will support either.

DDR4-3200 reg ECC, dual-rank.
Overclocking on Epyc Rome is not there yet. Maybe it never will be. But anyway, overclocking server-grade gear is highly unusual, to say the least.

[Chief Cookie]

thanks.

Found this on the wiki manual for the FDS software:

"FDS requires one or more fast CPUs and a substantial amount of random-access memory (RAM) to run efficiently. For minimum specifications, the system should have at least a 1 GHz CPU, and 1 GB RAM. The CPU speed will determine how long the computation will take to finish, while the amount of RAM will determine how many mesh cells can be held in memory.

1 GB RAM can hold around 106 cells. To understand the physical meaning, a 20 m x 10 m x 5 m computational domain contains 106 cells, when discretized with cubic cells of 10 cm side.

A large hard drive is required to store the output of the calculations. It is not unusual for the output of a single calculation to consume many gigabytes of storage space.

Smokeview needs an OpenGL graphics card. Look for graphics cards that specifically list OpenGL support for the operating system you intend to use."

seems to suggest more than one CPU is supported?

[flotus1]

I really don't know what to make of these contradicting recommendations. Seems like a good idea to contact them and ask for clarification.

[Simbelmynë]

Perhaps they talk about SMT and not NUMA? In any case, a clarification should be good.