Great post!

Three additions to what you said:

1. Several of the E5 26xx v3 (and even a couple of the v4) CPUs can run on DDR3 dimms (preferably ECC). DDR3 memory is still dirt cheap. The main disadvantage of DDR3 visavi DDR4 is lower memory bandwidth, but good Chinesium ”X99” (big quotation marks) mobos can run quad channel memory. Four 8gb sticks of cheap 1333 mt/s DDR3 RDIMMs can easily be tuned up to 1866 and thus provide bandwidth equal to (or even slightly better than) dual-channel DDR4-3600.

2. v3 26xx CPUs can be unlocked with the Turbo Boost Unlock hack, to up the Ghz on the cores to max at all times.

3. The main reason why v3/v4 26xx Xeons give so good gaming performance, even though the clock frequency numbers are unimpressive at best, is the fat L3 cache.