But, outside of heavy gaming and content creation, 2C4T is fine, these days, and 4C8T still way overkill. I use from 2C4T to 6C12T on a fairly regular basis, and with lightweight usage, I could probably pick up which one has the newest SSD, but any CPU differences will take loading the 2C4T down a good bit, and 4C8T remains smooth as butter even then.
I don't know about that. My DeskMini units have 2C/4T Kaby Lake CPUs in them, as does this one desktop I recently pulled out of storage to tweak, and my main desktop hooked up to the same screen, is a R5 1600, with 16GB of DDR4-2400 @ 2133 (because the ASRock BIOS doesn't support this DRAM at 2400.

), and I daresay, even mining on the Ryzen desktop, and with the CPU graph
COMPLETELY FILLED, it still feels a tad more responsive web browsing, than that Kaby Lake CPU, even unloaded.
However, this may be partially due to power-saving states and perceptive latency, it's subtle, but the CPU still takes time to "ramp up" to full speed to process every new web page, and that can be perceivable by some people. Whereas, under load, my Ryzen CPU stays pinned at all-core turbo speeds. Plus, Ryzen has 16MB of L3 cache, and the Kaby Lake has 3MB. Quite a difference.
I could perceive the difference in multi-tasking smoothness, even back in the Pentium II / CeleronA days, which is why I chose to overclock a PII-300 to 450, rather than a CeleronA, because it had 512KB, rather than 128KB, of L2 cache.
Basically, "jus sayin", that, these days, 4C/4T minimum for desktop tasks. 2C/4T for minimal tasks, if you're on a severe budget ($$$ or TDP). 2C/2T is pretty useless these days, the extra two threads help for smoothness.