[Noco]

Hello!

Please advise good cost-effective 2 CPU Hardware 2017-2018.

We have:
- 1 CPU i9 7980XE with Kraken X62
- ASUS S2066 PRIME X299-A RTL
- GeForce PCI-E 11264Mb 1080 Ti InnoVision (not helps actually)
- 64Gb DDR4 2133 MHz (4x16)
- 512 SSD for system
- 2x8 SATA RAID0 for storage
- Windows 10
- ANSYS CFX R17

Problems:
1. CPU was boosted with BIOS up to 4.2 MHz but then we need to return it to 2.6, because of the big load on CPU computer just shut down. Only changing battery in motherboard helps to return it to live, seems like CPU logic crash (not sure).

2. 1 CPU with 18 cores make it very slow with our tasks - we have 12 days waiting to get result.

If somebody have good experience with 2 CPU computer optimized for ANSYS CFX R17 - please advice.

[ghorrocks]

CFD needs fast CPUs. Many things do not make much of a difference for CFD: Hard drive/SSD speed, memory (as long as you have enough to fit the simulation in memory and that is usually only a few GB per CPU), graphics card etc - these all make little difference.

A single computer with 18 cores is unlikely to work very well. The memory controller is going to be a bottleneck where it is shared between 18 cores.

If you want to run 18 cores then the best system is likely to be a number (maybe 5?) stand-alone computers networked together with a fast network. Gigabit ethernet might just be OK for this, but you should look at faster networks like infiniband.

Designing computers to run large CFD simulations is not simple and requires careful research.

For the system you currently have, do a benchmark simulation from single processor, then 2,3,4,5 processors all the way up to the full 18. This will give you a lot of information to help optimise the system.

[Noco]

Glenn, thank you for answer!

I read some articles in this forum and other information before we bought this computer and I have general opinion that GPU do not work normally with CFX, only with Fluent and also not always, under special issues.

First I assume that 8 cores will be enough for us, but we suddenly received demand in simulations up to 5000 iterations, so I bought 18 cores CPU (I thought that it will be 120% faster because of core number/clock speed) - but it was not, the actual speed increased only about 50% (I change our 8 core i7 7820X to maximum for FCLGA2066 socket - 18 cores i9 7980XE).

Next step for us to increase performance is 2 CPU computer with Intel Xeon or AMD Epyc. Or to buy too more computers with i9 CPU with the same price and use parallel solver. I do not understand which is better.

[ghorrocks]

That is exactly why you need to benchmark your system carefully. CFD has very specific requirements on computing power, so taking the advice on computer speed from a solid modelling person or a gamer will not give you a good result.

[-Maxim-]

Our CFD workstations have Intel Xeons with 2 CPUS on a Supermicro motherboard. 64GB RAM. We have Nvidia Quadro graphics but that's not really important.
You should definitely ask around to find some experts for CFD workstations (there's also a separate section in this forum). From what I know, 2 x 4 core Intel Xeons used to scale better than 6 or 8 core CPUs. But now with the new Intel CPUs I've also read that the 8 core CPUs (Gold line) are the way to go. So maybe 2x 8cores on one mainboard.

[Noco]

Originally Posted by -Maxim-

Our CFD workstations have Intel Xeons with 2 CPUS on a Supermicro motherboard. 64GB RAM. We have Nvidia Quadro graphics but that's not really important.
You should definitely ask around to find some experts for CFD workstations (there's also a separate section in this forum). From what I know, 2 x 4 core Intel Xeons used to scale better than 6 or 8 core CPUs. But now with the new Intel CPUs I've also read that the 8 core CPUs (Gold line) are the way to go. So maybe 2x 8cores on one mainboard.

Ok. Thank you!

[Noco]

Originally Posted by ghorrocks

That is exactly why you need to benchmark your system carefully. CFD has very specific requirements on computing power, so taking the advice on computer speed from a solid modelling person or a gamer will not give you a good result.

I understand. I will move to Hardware section.