How many more cores instead of 3D cache?

What you're asking doesn't make sense..... like the 5900x and the 5950x are the only am4 cpu with more cores than the 5800x3d but both those have worse gaming performance than the x3D as they're made for different tasks. There is no cpu with enough to make up for it as thread ripper is a diff socket. If you're asking as a theoretical question that would have a lot factors because as cores go up clocks down but gaming benefits from asking for/getting info faster(be that higher clocks or more info readily available thru more cache) not getting more info at once

Just get the 5700x3d, more cores wont help you in this matter, this is a cache constraint issue. The R9 family does have double the cache vs the R5 but will still fall short of the 3d variant. It will last you a very long time.

3D cache is more important than cores for gaming.

How Many Cores to Compensate for Missing 3D Cache?
You cannot fully compensate for 3D cache with core count. The 3D V-Cache acts as a massive L3 buffer, reducing memory latency and improving frame consistency—something extra cores don’t address.

However:

6-core CPUs (like your 5600X) are the minimum for modern AAA titles.
8-core CPUs (5700X, 5800X) are the sweet spot for 1440p gaming.
12-core CPUs (5900X) help in hybrid workloads but offer diminishing returns in pure gaming.
🎯 Bottom Line: Upgrade to at least an 8-core CPU and pair it with 32GB of fast DDR4-3600 CL16 RAM to minimize the impact of missing 3D cache.

Has anyone ever done any analysis as to how "efficient' poe2 is at utilizing multiple cores/threads?

Apparently this patch comes with some updates that improve the multi-threading capability of the game and they're expecting some sequence related crashes or bugs as a result - makes me wonder how "tight" the multithreading or multicore usage was before.

A lot of the issues stemmed from the CPU scheduling that windows 11 was doing.

Welp... first you would have to know how many cores the game can really take advantage of. Having more than 6 won't do you any good if the game is using 4 at most. They said they did optimization because it wasn't using very many so who knows.

More cores doesn't scale due to resolution that was some odd commentary in this thread. Either the game can take advantage or not. If the game actually benefits from X3D and you can get one that works in your current motherboard then cool. I have a 7800x3d but couldn't tell you if the game benefits from it.. I play the game but I don't read reviews about how it performs on various hardware. I know that some other games I play really benefit from X3d which is why I bought it (didn't buy for poe2).

Also going forward memory isn't going to get any cheaper for a while. The entire problem is all these companies spending so much on AI and that is the main driver of DDR 5 costs. That's not going to stop in the next few years and both Samsung and Micron have said they don't plan on increasing memory production.

A lot of people are predicting an AI bubble and no one is going to spend a ton to increase production just to have demand drop off.

So if you play any games that benefit from X3D, an X3D chip that will work on your board might be a great idea and will last a decent amount of time.

I don't think you can find a better gaming CPU today on the AM4 platform than the 5800X3D. 3D V-Cache is super important, and gaming doesn't really utilize more than 8 cores anyway. The 5800X3D has both these things.

The 5900X/5950X have more cores, but those aren't really utilized by games, while they lack the 3D V-Cache which is actually important for games. Those CPUs are better for consumers that do various types of productivity tasks (without having to resort to the much more expensive Epyc processors) and while they are very capable gaming CPUs they are less so than a CPU with 3D V-Cache.

A problem though is that AMD has stopped manufacturing the 5800X3D. They're still available here and there but they're slowly disappearing.

So, you ask which CPU would have enough cores to compensate for the lack of 3D V-Cache, and the answer is there really isn't one. Purely for gaming you want to make sure your CPU has 8 cores, but any more than that will mostly be a waste. 12 cores instead of 8 cores will almost never give you any extra performance at all in games. At least not in the foreseeable future.