Best build under $5k in 2020 - OpenFOAM
 

Hi everyone, I need to build/buy a PC/Workstation/Server to run external aerodynamics simulations (compressible, sub/trans/supersonic) on OpenFOAM.

My budget for the build is around $5k. However, I'm not so expert in hardware stuff and I know that the simulation time is not just determined by the CPU, but also by other limiting factors, like RAM speed, channels configuration etc

What do you think would be, as of 2020, the best combo MOBO+CPU+RAM with the indicated budget and the type of simulations I'm aiming to run?

Thanks to anyone who could give me any advice, I'd really appreciate that.

https://geizhals.de/?cat=WL-1867596
Add storage to taste.

Thanks indeed, what would you instead propose for a $2k build? Just to have an idea of where the money goes in different budget ranges, and what the difference in performance would be.

Thanks for the availability

At 2000$, you have to decide where you want to make compromises.
Up to around 3000$, I would simply take the configuration I posted earlier, and leave out one CPU, 8 DIMMs and a CPU cooler. This gives you an easy and cheap upgrade path later on.
Below that mark, you will have to make some trade-offs. These could be:
1) Get a single Epyc 7302p and a motherboard with a single CPU socket. At the time of writing this, 7302p go for around 800€ new retail, and motherboards start below 400€
2) Use less RAM. 8x8GB instead of 8x16GB for a single socket. Of course, you need to know first how much memory you actually need
3) Skimp on other components. With only one CPU, you can get away with a cheaper ATX case and a cheaper power supply.
4) Save some more with a graphics card in the 100€ range

If you still can't hit your desired price range with these cuts, you will have to drop down further to "HEDT" territory. 8-12 core CPUs for Intels X299 platform for example.

Thanks for the advice, I now have a clearer picture.

The only thing I wouldn't be sure about is the amount of RAM needed for my purpose. As mentioned in my first post, my primary use is for OpenFOAM, and I don't think I will ever go over 10M cells.

On this forum I read that an approximation is 1GB of RAM for every 1M cells, so if this is somewhat true, the lower RAM configuration that you proposed (8x8GB for a single socket or 16x8GB for a dual socket would be more than enough even for the single socket build (?)

Maybe I'm underestimating the RAM requirements, I will do more research.

For only 10M cells, 64GB are definitely enough per socket.
With the olny caveat that model size tends to increase once you have a faster PC ;)