Current Workstation CPU Build - Value Picks?

Baum · July 23, 2021, 05:12

Hi all,

I'm looking for a new workstation setup for Fluent applications, and I am a bit overwhelmed by the choices, so I wanted to ask for your opinions on things before pulling out my wallet. I'll list some questions that came up:

- Are there some (current) general guidelines/experiences regarding CPU picks? Best value for the money, sweet spot of cores?

- Is there a clear recommendation regarding Intel vs. AMD at the medium-to-high end of the spectrum (20-64 cores, single node)?

- Would a 2x32-core setup work similarly/better/worse than a 64-core setup, e.g. 2x7543 vs. 7763? Does this change if the system runs 2/3/4 virtual machines in parallel?

- Is a setup with lower core amounts but higher clock speeds per core (or TDP) worth it in CFD tasks with some models that are not ideally parallelised (e.g. discrete phase models)? Example: 74F3 24c @ 3.2-4.0 GHz vs. 7543 32c @ 2.8-3.7 GHz.

Thanks in advance!

flotus1 · July 23, 2021, 06:37

General recommendations for CFD hardware [WIP]
should answer most of your questions.

Quote:

Is a setup with lower core amounts but higher clock speeds per core (or TDP) worth it in CFD tasks with some models that are not ideally parallelised

Whether it's worth it depends on your budget and how much more value you can extract from faster solver times.
But in general yes, these kinds of CPUs are ideal for applications that don't scale well. The Epyc 74F3 is pretty much the best allrounder CPU for dual-socket with up to 48 cores.

Baum · July 26, 2021, 03:29

Thanks flotus1, very interesting thread that I overlooked!

Sadly, the 74F3 is not available from our vendor, but the importance of memory bandwidth suggests to me that I will stick to 8-channel EPYCs with 256 MB of cache. Seems like the 7453 is the closest one there.

flotus1 · July 26, 2021, 04:07

Epyc 7453 is one of the CPUs to avoid in AMDs current lineup. There are reasons why its low price stands out from the rest of the bunch. Its low amount of L3 cache for example. And thanks to that, nobody really knows how many compute dies it actually has enabled.

For "value" picks in the 24-core range, it's either 7413 or 7443. They both only have 128MB of L3, but that is exactly the premium you pay for with an Epyc 74F3.

Baum · July 26, 2021, 11:05

Oh wow, I'm sorry, that was a typo on my end. I meant the 7543, not the 7453, because I wanted that 256 MB. The 64 MB 7453 seems like a bad choice indeed. So overall I'm leaning towards two 7543s and if I find that it bottlenecks too much at 32+ cores, then I'll turn it into two virtual PCs and suffer the small performance hit.

July 23, 2021, 05:12	Current Workstation CPU Build - Value Picks?	#1
Baum New Member Join Date: Dec 2019 Posts: 29 Rep Power: 6	Hi all, I'm looking for a new workstation setup for Fluent applications, and I am a bit overwhelmed by the choices, so I wanted to ask for your opinions on things before pulling out my wallet. I'll list some questions that came up: - Are there some (current) general guidelines/experiences regarding CPU picks? Best value for the money, sweet spot of cores? - Is there a clear recommendation regarding Intel vs. AMD at the medium-to-high end of the spectrum (20-64 cores, single node)? - Would a 2x32-core setup work similarly/better/worse than a 64-core setup, e.g. 2x7543 vs. 7763? Does this change if the system runs 2/3/4 virtual machines in parallel? - Is a setup with lower core amounts but higher clock speeds per core (or TDP) worth it in CFD tasks with some models that are not ideally parallelised (e.g. discrete phase models)? Example: 74F3 24c @ 3.2-4.0 GHz vs. 7543 32c @ 2.8-3.7 GHz. Thanks in advance!

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July 26, 2021, 03:29		#3
Baum New Member Join Date: Dec 2019 Posts: 29 Rep Power: 6	Thanks flotus1, very interesting thread that I overlooked! Sadly, the 74F3 is not available from our vendor, but the importance of memory bandwidth suggests to me that I will stick to 8-channel EPYCs with 256 MB of cache. Seems like the 7453 is the closest one there.

July 26, 2021, 04:07		#4
flotus1 Super Moderator Alex Join Date: Jun 2012 Location: Germany Posts: 3,399 Rep Power: 46	Epyc 7453 is one of the CPUs to avoid in AMDs current lineup. There are reasons why its low price stands out from the rest of the bunch. Its low amount of L3 cache for example. And thanks to that, nobody really knows how many compute dies it actually has enabled. For "value" picks in the 24-core range, it's either 7413 or 7443. They both only have 128MB of L3, but that is exactly the premium you pay for with an Epyc 74F3.

July 26, 2021, 11:05		#5
Baum New Member Join Date: Dec 2019 Posts: 29 Rep Power: 6	Oh wow, I'm sorry, that was a typo on my end. I meant the 7543, not the 7453, because I wanted that 256 MB. The 64 MB 7453 seems like a bad choice indeed. So overall I'm leaning towards two 7543s and if I find that it bottlenecks too much at 32+ cores, then I'll turn it into two virtual PCs and suffer the small performance hit.