It will be interesting to see whether they can match Intel in single-threaded performance across the board, and not just some carefully-selected benchmarks. This would be the first time since the Core2/Athlon64 days.
AMD now has 256-bit AVX2 units, but unlike Intel, they don't need to downclock due to 7nm TSMC's lower power requirements compared to Intel's 14nm process. This should also affect 128-bit AVX instructions. It should be possible to reorder and push 2 through the pipeline at the same time in a lot of circumstances.
To be clear, the existing chips had two 128-bit vector units, and the new ones have two 256-bit vector units. So that would get you 4 total.
Also each unit, at least on existing chips, is capable of either a single FMA or a completely independent multiply and add at the same time. I don't think Intel chips can do this?
I have been running 4 players with one of the most taxing modpacks on a mid tier digital ocean VPS with no hitches. Not many players I guess but in case you were curious if you could use a VPS. Even when we had multiple excavators sending thousands of entities through sorting pipelines it was stil doing surprisingly well.
It's a vanilla server and I also get around 4 players. The real problem occurs when people are generating new terrain while flying on an elytra, sometimes causing the server to crash altogether. When not exploring, it will frequently report "Can't keep up!" messages even when hanging around spawn, which I think might be due to the truly insane amount of hoppers we have (although haven't seen this as much in the recent update).
If you're curious, the CPU is a i5-3570K @ 3.40GHz. The game is certainly playable, but it struggles under load like I described.
People have been banging their heads against the 'rewrite this software to take advantage of multiple cores' wall for decades. The lack of progress is telling. For a straightforward example, look at the second half of this Factorio update blog: https://www.factorio.com/blog/post/fff-215
Factorio is a sim game that you would think on first consideration would hugely benefit from a multithreaded design. It turns out that doing so is actually slower(!). And although this example is pulled from a game, it is essentially the same story again and again, no matter what the subject.
Now consider the second half of your statement- that the main benefit of multi-core processing is that it provides more CPUs, so that if any one gets choked, the general environment continues to operate.
(Which is true, and a great advantage of having a multi-core CPU.)
But consider a little deeper, too. If the first, best defense we have regarding multi-core designs is that they are simply more single-cores to have on hand, what does that say about the relative value of parallel processing vs. single-thread performance? Inherently serial workloads dominate across the board, in every field. The few parallel problems we have, we have because people have put a lot of brain sweat in to figuring out what, exactly, we can even do with all these cores lying around.
Meanwhile, there are entire classes of problems that are simply waiting for better single-thread performance before we can move ahead.
This is a very real problem, and it isn't going away.
The people who would benefit from more cores have the server specific lines of CPUs to choose from, so that makes consumer grade CPUs a compromise between core count and single core performance.
And some games (like some Source-engine titles) crash if you have a high core count.
I certainly benefit from the higher core count because I usually have a VM, 40 browser tabs, Slack, and a bunch of other stuff open at any given time, but my parents would see no benefit with their 5 tabs + iTunes + Word usage.
I am hopeful for the actual third party benchmarks.
This is why when looking at iMacs, I'd rather get the iMac than the iMac Pro. Multiple cores just aren't as important to me as is single-core performance.