[erock]

Originally Posted by Snowfiend

Which software do you intend to use?
Ansys Fluent, Mechanical
Are you limited by license constraints? I.e. does your software license only allow you to run on N threads?
No license restrictions.
What type of simulations do you want to run? And what’s the maximum cell count?
• Two-phase flow with highly velocity fluid speeds such as MACH 3 with fluid and solid particle injection,
• Steady/ transient,
• External & internal flow.
• Pressure, Density, Simple, Coupled solver
• 2nd order analysis solvers
• 1-20 million cells
• Static Mechanical analysis
If there is a budget, how high is it?
$6,000 USD
What kind of setting are you in? Hobbyist? Student? Academic research? Engineer?
Engineer/Researcher
Where can you source your new computer? Buying a complete package from a large OEM? Assemble it yourself from parts? Are used parts an option?
Can build in-house, using existing parts and items from ebay(china).
• 12x 16GB DDR5 ram 4800 ECC 2Rx8 - (196GB total)
• 1000W corsair platinum(purchased new)
• Gigabyte MZ33-AR0
• Noctua air cooling NH-U14S TR5-SP6
• NZXT Phantom Case (existing PC case)
• GTX 1080 8GB.(existing)
• AMD EPYC 9554, L3 =256 MB, (3.1- 3.75)GHz, 64 core ($3000)
OR
• AMD EPYC 9654 QS, L3=384 MB, (2.15-3.5)GHz, 96 core($3000)


Which part of the world are you from? It’s cool if you don’t want to tell, but since prices and availability vary depending on the region, this can sometimes be relevant. Particularly if it’s not North America or Europe.
Sydney, Australia.
Anything else that people should know to help you better?
• Parts will be second hand(ebay- understood risks involved)
• First CFD build.
• Wake on LAN - remote login to initiate analysis

Additionally, I have researched into the core count and diminishing returns, I understand that after 48 core the efficiency diminishes quickly but the 9454 arent common. For the same price between 9554 and 9654 QS I am at a fork in the road. I can see good performance from 64 core but for the same price I can get the 96 core with a larger L3 cache, so I'm wondering if the 9654 lower frequency and higher cache rate would be a significant improvement over a 9554 lower cache and higher frequency.

If you are interested in maximizing your price per performance ratio, I recommend building a small Epyc Rome cluster given that prices are very very low now on the second hand market. Here is the approximate pricing utilizing some of the better sellers on Ebay:

• Dual socket H11DSi rev 2 mother board: $450-550 (16 channel memory)
• 48 core Epyc 7k62 unlocked ~$300: $600 for 96 cores
• 16GB DDR4 3200 ECC RDIMMs are going for ~$30/stick (NEMIX budget RAM) ~$50/Stick (Named Brand like Crucial): $624-800 for 256 GB RAM (16*16GB)
• 2xNH-U14S coolers (~$200)
• You could directly connect these machines using old dual port ConntextX-3 of ConnectX-4 (~50 to $150 per machines)
• 1000W power supply: $190
• Fast NVMe Drive: $190
• 4 1500 rpm Noctua fans: ~$80

So a powerful EPYC Rome 256GB 96 core (16 memory channel) node can be built now for around $2400. For a budget of $6000 you could easily build two nodes and directly connect them for distributed memory parallel computing (add ~$300 for two used ConnectX cards and DACs). If you go with budget RAM use a seller with a good return policy and be ready to return 5-10% of your sticks. If you don't want that hassle just go with name brand RAM.

[damon707]

Hi everyone,
Below my answers to the questions.

Which software do you intend to use?
OF, star-ccm+

Are you limited by license constraints? I.e. does your software license only allow you to run on N threads?
No license restrictions.

What type of simulations do you want to run? And what’s the maximum cell count?
Various types of cfd simulations. Nothing in mind right now.
Max cells will be limited by my specs /budget so not really sure.

If there is a budget, how high is it?
$2,500 USD

What kind of setting are you in? Hobbyist? Student? Academic research? Engineer?
Engineer

Where can you source your new computer? Buying a complete package from a large OEM? Assemble it yourself from parts? Are used parts an option?
Myself from parts.
Used parts are an option if they are worth the "risk".



Which part of the world are you from? It’s cool if you don’t want to tell, but since prices and availability vary depending on the region, this can sometimes be relevant. Particularly if it’s not North America or Europe.
Europe

Anything else that people should know to help you better?

I'm looking to build a workstation here. Obviously server builds (epyc/xeon) will run much faster than workstation cpu builds. However, I'm looking to build a general purpose workstation that will run cfd faster than any other workstation on this budget.

Thanks in advance for your input.