|Model||Price (cheapest)||Cores /|
|Ryzen 7 2700X||-||8 / 16||3.7 GHz||4.3 GHz||16 MB||105 W|
|Ryzen 5 5600X||212€||6 / 12||3.7 GHz||4.6 GHz||32 MB||65 W|
|Ryzen 7 5700X||283€||8 / 16||3.4 GHz||4.6 GHz||32 MB||65 W|
|Ryzen 7 5800X||310€||8 / 16||3.8 GHz||4.7 GHz||32 MB||105 W|
|Ryzen 7 5800X3D||459€||8 / 16||3.4 GHz||4.5 GHz||96 MB||105 W|
|Ryzen 9 3900X||421,9€||12 / 24||3.8 GHz||4.6 GHz||64 MB||105 W|
|More cores and cache||similar gaming performance with less power and cheaper|
|more power/heat||same # threads as 2700X ("psychologically" feels like a smaller upgrade)|
|recommended cooler upgrade to optimize boost performance|
The 5600X has incredible gaming value, but I can't see myself going for a lower core count, so that leaves the 5700X as the closest contender. I think in the end it will come down to price and since the 5900X is an older part I expect it will have a bigger discount (%) around Black Friday week.
For practical intents and purposes, the 5900X has 2x32MB of L3, not 64MB. It does have somewhat higher cache bandwidth in AIDA64, but that's about it. As with Ryzen 3000 and 7000 there is no direct connection between the two CCDs (cross-CCX communication goes the long way through the IO die and two IFOP links), and inter-CCD latency has always been slow, so in practice there's really no reason to consider the 5900X to have an L3 advantage. If any core was able to access 64MB in a meaningfully fast way, the 5900X/5950X would already have stood out the way the 5800X3D does.
I've spent about a year and half with my 5900X and watched its behaviour mature from AGESA 1100 to 1207, through a bunch of different boards, and Windows 10 to 11. I know exactly how you feel about the "psychological" upgrade. ST-wise and MT-wise it is a very strong CPU, and only gets stronger if you put it under custom water - but as the AM4 lineup sits right now, it would be my last choice for gaming, only ahead of the APUs. As far as the few games that I've seen utilize enough threads to matter, it's functionally a 5600X.
There is one unexpected feature that came of Windows 11, is that 5900X/5950X are essentially treated as big.little CPUs (think 12900K) in the new OS. Demanding ST tasks can be reserved for CCD1 cores (which always houses your best cores), whilst the scheduler will pick a core on CCD2 to handle the vast majority of your daily background tasks. I'm not committing to saying that it's a benefit, however, because in practice that CCD2 background core actually hogs a lot of gaming load too instead of giving it to Preferred Cores, so inter-CCD load juggling happens very often as a result possibly reducing performance. Windows 10 behaves very conventionally, meaning CCD2 is basically always dark until you fire up an all-core workload.
On the temperature front, however, it's not hard to cool. I understand you have a smaller AIO, but it should not be a problem (I'd be more worried about the age and reliability of your AIO).
I paid a rather mediocre price for my 5800X3D, but I just can't see any reason why I would go back to my 5900X. I just don't do enough to make use of those cores.