In all of these charts, we have another line with PCIe Gen but we decided to go with the number of lanes, then the effective Gen3 bandwidth multiplying lanes by 2 for Gen4 lanes. We are still early in the Gen4 product cycle which means there are still more Gen3 devices out there. In the case of the Ryzen 3950X, despite having similar PCIe bandwidth as the Core i9-10980XE, using a PCIe Gen3 x16 GPU and x16 NIC (e.g. a 100GbE adapter) is not possible. With more lanes, the HEDT parts can handle that scenario.
As some background here, I personally have been on the journey from the dual Intel Xeon workstations (from Nahelem to Broadwell.) A reason I cannot use a mainstream part is the relatively small maximum memory size (64GB with full speed memory) as well as the lack of PCIe lanes. 1GbE and 10GbE are great, but even my home network has been on 40GbE/ 25GbE since 2015 just to get to network storage. That means I need more PCIe lanes for networking, local NVMe, and a GPU. The mainstream platforms simply fall short of servicing this use case. That is where HEDT parts, like the Core i9-10980XE and Threadripper parts, show an enormous benefit.
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When we again truncate results, one can see the appeal of the Intel Xeon W-3275, albeit at a higher price. If the features like AVX-512 and large ECC memory capacities are going to be used, then Intel has a strong value proposition. Conversely, if one does not need those features, then the new Threadripper parts offer a strong value. At only $979, when we look in this view the Core i9-10980XE looks like a part appropriately priced between the Ryzen 3950X and the Threadripper 3960X, so long as the platform features are important.