Quad socket LGA2011 workstation?
 

Hello and thanks for the hospitality!
I am currently feeling the need to upgrade my workstation which is getting rather old while my FEA models are getting larger.
My system is a dual Xeon X5670 running with 192GBs of DDR3 ECC RAM which is the maximum memory you can fit. And in FEA, memory is gold. You need large amounts of RAM more than anything else.
With current prices of DDR4 memory i doubt i can invest in a modern workstation. So i am evaluating the solution of getting a quad socket Xeon E5-V2 motherboard, fit 4x E5-4650V2 CPUs (40 physical cores for $1K is not bad) and adding some more DDR3 memory in it, while making use of my current DDR3 memory. The motherboard in question can take a maximum of 1TB of DDR3 so this is good.


But will it be futureproof?

How could this system possibly compare with let's say a dual EPYC 7301 with modern DDR4 memory?

I know it is tempting, but there are some caveats. The first one is finding the hardware itself. Quad-socket motherboards are pretty hard to find. They usually have some proprietary form factors and power connectors which makes finding a suitable case and power supply tedious.
Your best bet is buying a decommissioned server, but as usual this hardly qualifies as a workstation that can sit under your desk.
And then Xeon E5-4xxx are not the best CPUs for this task because they only have 2 QPI links. This means that not all CPUs can communicate directly with all other CPUs which significantly increases latency and reduces bandwidth.
Xeon E7 would be better suited for this task due to 3 UPI links which allows a direct connection between all 4 CPUs, similar to what infinity fabric does to connect all 4 dies inside an Epyc CPU. Such a system would hold up pretty well against dual-socket Epyc in terms of performance. Sourcing the necessary parts and turning them into a workstation might be difficult though.