[diogoperdigaodp]

Hey there.

I'm building a new PC for CFD work in University, since I only have a laptop.
Because I don't know much about hardware requirements for CFD, I would like some help.
I would like to choose between these (although I'm open to suggestions):
Ryzen 5 5600X
Ryzen 7 5700X
i5 10400
i5 11400
i5 12400
i5 11600
i5 12600
i7 11700


Is 64 GB of ram worth it over 32 GB?


Thank you!

[wkernkamp]

The best Ryzen is benchmarked here:

Originally Posted by Simbelmynë

5800X3D, 2 x 8 GB DDR4 Rank1 @ 3200 MT/s (14-14-14-14-28,1T)
OFv9, OpenSUSE Tumbleweed, GCC 11.2, kernel 5.17.4

The 1 core result is amazing and the 6 core result is pretty decent as well. I assume this is the fastest dual channel CPU for CFD right now. Well at least until someone with a large wallet can post some results for Alder Lake with DDR5 @ 6400+ MT/s EDIT: (missed the post a couple pages back, the i5-12600 with DDR5 @ 6000 MT/s is indeed faster, and not terribly expensive with a B660 motherboard, so definitely a better value if buying an entire new computer)
The single-core result is 33% faster than the 5900X (from this thread). The 5900X has a single core boost up to 4.8 GHz while the 5800X3D only boosts to 4.5 GHz. Apparently the extra V-Cache is more important than the extra single-core speed.

 cores       Simulation     Meshing
#                (s)      (min.sec)
1             314.21        12m23s
2             201.98        8m21s
4             149.98        5m05s
6             138.55        4m02s

Will update if I manage to push the memory and IF to 1800 MHz.



EDIT:
2 x 8 GB DDR4 Rank1 @3800 MT/s (16-16-16-16-32, 1T)

cores    Simulation         Meshing
#           (s)             (min.sec)
1            304              12m14
2            188              8m12
4            135              4m58
6            124              3m55
8            122              3m28

I have some results where the IF manages 2000 MHz, which admits 4000 MT/s in 1:1. Not fully stable though so i need a few more days to learn this particular CPU. The interesting part is that higher IF speeds means that the L3 cache latency decreases, so it not only admits higher bandwidths.

[wkernkamp]

The best Intel is benchmarked here:

Originally Posted by ErikAdr

The version openfoam2112 did not provide an executable of 'surfaceFeatures' and that was why I could'nt get any results for the motorbike benchmark. I gave up on openfoam2112. I went for a go with version 9 from openfoam.org. First I installed ubuntu 20.04.3 (standard installation) and then I followed the guide from openfoam.org to install on ubuntu. Next I downloaded the 'bench_template.zip' in post 447 by Simbelmynë and then I followed the guide from step 4 to 7 in post 448 by linuxguy. Everything worked in first attempt. That was a strange feeling after the many previous attempts.



I have build a quite low end computer, but with quality components. It is using a i5-12600 cpu with two channel DDR5 Ram. I'm pleased with the performance.



12th Gen Intel(R) Core(TM) i5-12600 DDR5 @ 4800

# cores Wall time (s):
------------------------
1 427.45
2 234.12
4 149.91
6 125.75



12th Gen Intel(R) Core(TM) i5-12600 DDR5 @ 5600

# cores Wall time (s):
------------------------
1 410.79
2 219.95
4 137.39
6 112.58

12th Gen Intel(R) Core(TM) i5-12600 DDR5 @ 6000

# cores Wall time (s):
------------------------
1 399.94
2 213.75
4 131.87
6 107.09

[wkernkamp]

The amount of memory depends on problem size and code. I would go with 64GB.

[diogoperdigaodp]

So, I'm going to start a masters in September.
Mechanical Engineering, specializing in Thermal/Fluid Mechanics.


I currently have a 5700X with 2x 8 GB DDR4 3200 MHz.


What's the advantage of reg ecc memory?
Can it work on a normal system?


Would an E5 2680 V4 with a chinese motherboard be better? What about 2?


What about a Xeon Gold 6138?


My last options would either be a 5900X, 12600K or 14600K.


Any help would be appreciated.
Thank You

[Simbelmynë]

There are many options that would be better. It all depends on your budget. The consumer CPUs you mention are a sidegrade, not a real upgrade. Reg memory is not available for those platforms, nor would it help with simulation time. It is good for system stability if you have large amounts of RAM.

So, budget and software. Follow the sticky thread posted by Flotus1.

[wkernkamp]

Originally Posted by diogoperdigaodp

So, I'm going to start a masters in September.
Mechanical Engineering, specializing in Thermal/Fluid Mechanics.


I currently have a 5700X with 2x 8 GB DDR4 3200 MHz.


What's the advantage of reg ecc memory?
Can it work on a normal system?


Would an E5 2680 V4 with a chinese motherboard be better? What about 2?


What about a Xeon Gold 6138?


My last options would either be a 5900X, 12600K or 14600K.


Any help would be appreciated.
Thank You

For CFD memory bandwidth is important. The memory on your 5700X system can be run at +/- 3800 MT/s. That is a speedup of 19%. You also need a bit more memory. Get at least 2x16GB. Other than that, I would keep the current system and save your money until you are running cases that are too slow on this machine.