"possible" again its only a benefit if it uses that xtra cache. cpu is actually slower if it doesnt (due to lower clockspeeds than x version)
also that was on a 5900x (which means likely even less benefit as its 5800x)
AMD's already said AM5 will have similar life that AM4 had meaning its gonna have a long term upgrade path.
also pcie5.0 (more future proof)
also do u need to upgrade? a 3900x is a good cpu.
I know of the scenarios in which the extra 3d cache is appreciated and that it has lower base clocks than a typical 5800x, I do not need any information on the differences between it and other similar CPUs.
AM5 will surely have a long lifespan but since I am currently on AM4 and do not see myself building again for 4+ years there is no benefit creating e-waste out of my current computer to spend 600+ dollars on a new platform.
Couple of things about "future proofing" as it seems pertinent. First off, its an objectively useless thing to attempt to achieve when 2-4 years later something many times faster will dwarf any performance 5 has over 4 et cetera. Secondly, PCIe 5 is nearly useless as it is already much faster than nearly all of the products currently on the market.
Need to upgrade? Well that is a question that has no answer that is not opinionated, but since that is my opinion I will say, yes. The 3900x is more of a productivity chip than I require compared to the things I will benefit from like fewer, more potent cores. I agree that the 3900x is still a completely relevant chip and I have not decided if I am going to get a 5800x or 5800x3d yet, I await benchmarks of the 5800x3d.