EPYC 7551p vs dual Xeon Gold 6126

y2k_o__o · December 11, 2023, 02:42

My main workstation is a Xeon W3-2435 with 8x 8GB DDR4-2933 for design work + drawings, but I also want to build a 2nd machine just purely for CFD so that it doesn't occupy my main workstation. The majority of work I do is Solidwork Flow simulation with roughly about 30-60 million cells per simulation.

I was given a pair of Xeon Gold 6126 (2 x 12C/24T) for free that I want to make use of it as a CFD machine, but I have researched that dual LGA3647 boards aren't cheap. On ebay, a cheap combination of Supermicro board + EPYC 7551p are roughly about the same of a used dual LGA3647 board.

I already have a lot of 16GB Crucial DDR4-2666 RDIMM that I plan to populate the 2nd workstation full dimm slot. With the same amount of memory, will I have quicker result with dual 6126 (2x12C/24T)or 7551p (32C/64T) ?

Assuming I am populated full dimm slot with memory. Here's the maximum memory bandwidth I can get:
Dual Xeon Gold 6126 (Hexa) - 2x 119.21GB/s = roughly 240 GB/s
7551p (Octa) - 158.95 GB/s

What's an estimated simulation time for 30 million cells?

flotus1 · December 11, 2023, 03:50

I think the dual Xeon system will serve you much better.
It has more memory bandwidth, faster cores, and a less complicated NUMA topology with lower latency. So even in traditional CFD solvers like OpenFOAM, it should be faster. And Solidworks flow solver might not behave quite so nicely, so the last two points on that list are particularly important.

I know how much it sucks that the motherboards are so expensive. But in the end, you say both options are about the same total cost. And quite frankly, 1st gen Epyc in 2023 just isn't worth it. Total performance and price/performance of later generations is so much better. Coming from someone who is still using 1st gen Epyc in my main workstation.

I can't really estimate how long a simulation will take. There are just too many variables here, and I don't know much about Solidworks Flow.

moving-boundaries · December 14, 2023, 18:24

You can plug dual 6126 into older workstations like Lenovo P720/P920, Dell T7820/T7920, HP Z6/Z8 G4. I think you can get one of those barebones for around $200-300 (e.g. https://pcserverandparts.com/build-y...0-workstation/)

December 11, 2023, 02:42	EPYC 7551p vs dual Xeon Gold 6126	#1
y2k_o__o New Member Join Date: Mar 2011 Posts: 5 Rep Power: 15	My main workstation is a Xeon W3-2435 with 8x 8GB DDR4-2933 for design work + drawings, but I also want to build a 2nd machine just purely for CFD so that it doesn't occupy my main workstation. The majority of work I do is Solidwork Flow simulation with roughly about 30-60 million cells per simulation. I was given a pair of Xeon Gold 6126 (2 x 12C/24T) for free that I want to make use of it as a CFD machine, but I have researched that dual LGA3647 boards aren't cheap. On ebay, a cheap combination of Supermicro board + EPYC 7551p are roughly about the same of a used dual LGA3647 board. I already have a lot of 16GB Crucial DDR4-2666 RDIMM that I plan to populate the 2nd workstation full dimm slot. With the same amount of memory, will I have quicker result with dual 6126 (2x12C/24T)or 7551p (32C/64T) ? Assuming I am populated full dimm slot with memory. Here's the maximum memory bandwidth I can get: Dual Xeon Gold 6126 (Hexa) - 2x 119.21GB/s = roughly 240 GB/s 7551p (Octa) - 158.95 GB/s What's an estimated simulation time for 30 million cells?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Xeon Gold Cascade Lake vs Epyc Rome - CFX & Fluent - Benchmarks (Windows Server 2019)	SLC	Hardware	18	June 13, 2020 16:48
Intel xeon gold vs AMD epyc build recommendations?	ahmedna8	Hardware	9	January 18, 2020 23:12
New 128 mini cluster - Cascade Lake SP or EPYC Rome?	SLC	Hardware	8	December 16, 2019 16:25
Xeon Gold workstation config.	Blanco	Hardware	14	June 8, 2019 01:55
Dual Xeon E5-2687W v3 or i7-5960X?	DoeBoy	Hardware	1	August 25, 2015 15:44

December 11, 2023, 03:50		#2
flotus1 Super Moderator Alex Join Date: Jun 2012 Location: Germany Posts: 3,426 Rep Power: 49	I think the dual Xeon system will serve you much better. It has more memory bandwidth, faster cores, and a less complicated NUMA topology with lower latency. So even in traditional CFD solvers like OpenFOAM, it should be faster. And Solidworks flow solver might not behave quite so nicely, so the last two points on that list are particularly important. I know how much it sucks that the motherboards are so expensive. But in the end, you say both options are about the same total cost. And quite frankly, 1st gen Epyc in 2023 just isn't worth it. Total performance and price/performance of later generations is so much better. Coming from someone who is still using 1st gen Epyc in my main workstation. I can't really estimate how long a simulation will take. There are just too many variables here, and I don't know much about Solidworks Flow.

December 14, 2023, 18:24		#3
moving-boundaries New Member Daniel Join Date: Nov 2023 Posts: 6 Rep Power: 2	You can plug dual 6126 into older workstations like Lenovo P720/P920, Dell T7820/T7920, HP Z6/Z8 G4. I think you can get one of those barebones for around $200-300 (e.g. https://pcserverandparts.com/build-y...0-workstation/)