AMD's new Ryzen 7000 series "Zen 4" processors are now official, but the company didn't detail absolutely every single detail on its Zen 4 processors... but now we have some of those holes filled by Angstronomics.
AMD is manufacturing the Ryzen 7000 series CCDs with TSMC's new 5nm process node, with each 8-core CCD featuring 6.57 billion transistors, which is a 58% upgrade over the Zen 3-based CCDs which are made on TSMC's 7nm process node with 4.15 billion transistors. The Zen 4 cores are codenamed "Persephone" according to Angstronomics, something we heard in rumors in the hours before the Zen 4 launch, while the CCDs are codenamed "Durango".
The reason that we have a huge transistor density upgrade is that AMD is using a new architecture, more cache, and AVX512 instruction support into Zen 4. The Zen 4 chiplet has 90 million transistors per square mm, with each of the Zen 4 cores featuring 1MB of L2 cache (double that over Zen 3) while the cache area is smaller. This means that a larger percentage of total die area is used, but logic area has doubled in transistor density... and that's not a good thing.
This means that cooling AMD's new Ryzen 7000 series "Zen 4" CPUs will be an issue... as you're temperature limited for the most part. This is because the 72.5 mm² die with maximum turbo power reaching 170W results in 1.92W per mm² and that's without worrying about the 230W limits of max peak power (PPT). If we compare this to Zen 3, the CPU had a 83.74 mm² die with 105W TDP so 1.25 W/mm².
Angstronomics adds that the cooling difficulty and higher power limits of AMD's new Ryzen 7000 series "Zen 4" desktop processors will have to change to a "laptop-like approach" when it comes to cooling. This means instead of fixing CPU clock speeds and power limits, the CPU is now purely temperature limited. Now you're maximum performance on a Zen 4 CPU will be dictated by the cooler that you're using.
This is why the huge triple-fan 360mm AIO coolers are used on flagship CPUs like the Intel Core i9-12900K to get the best out of them, is purely power = heat = cooling capacity. AMD's new Ryzen 7000 series "Zen 4" processors seem to be no different, in fact, it seems to be even more highlighted: prepare to have, or to buy a high-end AIO cooler for the higher-end Ryzen 7000 series CPUs, especially for the Ryzen 9 7900X and Ryzen 9 7950X processors.