The Red team has silently announced the AMD Ryzen 9 5900 with 12 Zen 3 cores and 24 threads, consuming just 65W TDP. This is the reason why its base clock speed is set to just 3.0GHz but goes up to 4.7GHz boost clock speeds when required.
Whereas, the Ryzen 9 5900X has a 3.7GHz base and 4.8GHz boost clock frequencies, thanks to a higher 105W TDP. Coming to the cache, much like the X variant, the Ryzen 9 5900 sports 64MB total L3 cache and 6MB total L2 cache.
It is an unlocked CPU like all other Ryzen processors and is based on TSMC 7nm FinFET process; the rest all the specs remain similar to that of the Ryzen 9 5900X.
However, the Ryzen 9 5900 will be an OEM-only CPU, so you cannot buy it separately, though and it will be seen on many pre-built PCs by various OEMs.
@TUM_APISAK also spotted the CPU on userbenchmark and the performance seems quite good though. We will soon be bringing the review of the regular AMD Ryzen 9 5900X on our blog, so stay tuned.