[3nhu1]

Hi, please could I seek some advice on a CPU upgrade? I am starting a PhD and wish to upgrade my personal PC for CFD work.

Curently on amd ryzen 1600, 2x8gb ddr4-3000 ram, geforce 1060, motherboard is b350-i so limited to 2 memory channels only, as you can imagine CPU is pretty slow and hence wishing to update it. (I may have funds for a research work PC very latterly next year £2-3K but am not sure of the budget yet hence wanting to update my own first, on a sidenote I may be tempted to look at a used epyc/xeon or new threadripper pro then)

Other questions based my circumstances are below
1. Will be using simpleware scanIP and ansys CFX
2. License constraints - Not sure as was hard to check under university license but can use up to 20 cores at least
3. What type of simulations do you want to run? Blood flow simulations And what's the maximum cell count? 570 000 elements
If there is a budget, how high is it? less than £500 for new CPU
4. Part sourced from EU / online

Based on the motherboard I could look at 5800X3D (8cores/96mb cache) or 5900X (12cores/70mb cache) or 5950X (16 cores/72mb cache). Prices for all the processors are similar ~400 although 5900x is cheapest. I understand I am limited by the motherboard so will have 2 memory channels. Regardless could I ask what anyone who knows more about hardware thought would be preferable? Thank you

[wkernkamp]

You should choose the 5800X3D because the large cache helps performance.


The good performance shown below will also apply to other CFD software:

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

 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

[flotus1]

The 5800X3D is probably the best CPU for the socket. But better check that your mainboard has a bios available that supports it. I'm not 100% on that, but from memory, supporting the last CPUs on B3xx boards was up to the board manufacturers.

[3nhu1]

thank you both for your helpful comments on CPU choice
I have flashed the bios yesterday and SMU checker states it is supported so it should be alright - also emailed asus to confirm before purchase

[3nhu1]

thanks for feedback, upgraded yesterday and all good!