Have you ever played Ghost Recon Wildlands on a 4 core CPU? Or Shadow of the Tomb Raider? Or Battlefield V? Assassin's Creed Osyssey? These are just a FEW of the games that run far better on a 6c/12t processor than on a 4 core processor, with or without hyperthreading.
The claim of Intel being better at gaming is indeed true, but if you have ever seen a single unbiased review in your entire life, you'll know that Intel is better in VERY specific scenarios, and with a 120 or even 144 Hz monitor, you'll never tell the difference between an Intel chip and an AMD chip, let alone on a 60 Hz monitor. The fact of the matter is that the numbers you are claiming for showing Intel's superiority are very likely to be extremely biased - consider the very obvious bias that the 3950X is obviously running at its out of the box configuration, while the i7 has been overclocked on a very high-end liquid cooler to reach that 5.1 GHz figure. Along with that obvious difference, there's also the fact that the 3950X is a 16 core 32 thread processor while the i7 is a measly 8 core 8 thread. If you think comparing these two chips (with one being a $750 chip and the other being a $400 chip) is a fair comparison, you need help. The 3950X is obviously not aimed at gamers anyway.
My point being, any reasonable person knows that Intel being better at gaming is now only a thing that people say, but no one actually believes Intel is better for pretty much anything, except if you want to play less demanding eSports games with a 240 Hz monitor and an overkill GPU.
And also, an i3 is absolutely not a workstation CPU - it's the exact opposite. Do you even know what a workstation means? It doesn't mean a PC on which you do office stuff - a workstation PC is supposed to have high-end hardware for demanding things like video editing, animation, etc. An i3 is an entry-level gaming or office PC CPU, not a workstation CPU.