High-end workstation
 

Hello,

I am still looking to build a powerful dual CPU workstation to use for my icing simulations. I will be working on mainly 2D problems but also 3D with up to max 3million cells. I will be using ANSYS software (FENSAP-ICE) which scales very similarly to FLUENT. I have a total of 80 licenses available but they are limited to 16 cores for each task. We will probably go for 128GB (8x16GB) 2400MHz DDR4 RDIMM ECC working memory.

But I am still wondering what CPU I should prefer. E5-2687W v4 (12C @ 3GHz) seems to be the economically best solution but E5-2697A v4 (16C @ 2.6GHz) would offer a bit more performance on paper. Any thoughts on how much performance increase I could expect and if it's really worth the additional money?

It is probably not worth the extra money. You might want to have a look at this: https://www.cfd-online.com/Forums/ha...-overwiew.html
With 3 million cells maximum, scaling on large numbers of cores will be less than ideal. So go for the CPU with less faster cores. Better spend the extra money on more fast storage. Btw: I hardly think that you will have any use for that amount of RAM with such small simulation models.
Just don't overthink the purchase. You will never make up for the time lost delaying the decision for a few more weeks, no matter how fast the workstation is.

Well said flotus1.
The 2687W will be faster if you are limited to 16 cores per computation. This is due to the higher frequency: 3GHz vs 2.6GHz.