There is mounting evidence that AMD plans on releasing a Ryzen 9 3900 CPU, joining the family of 3rd gen Ryzen 3000 processors, which occupy many positions on our best CPU for gaming list. The latest clue comes from Biostar, which updated its CPU support list with the unannounced entry, along with a Pro version of the same chip.
The entries sparked some interest online, and Biostar subsequently removed them. However, our friends at TomsHardware managed to grab a screenshot before they disappeared:
The assumption is that these will both be 12-core/24-thread processors, just like the Ryzen 3900X, one of the best CPUs for gaming (and everything else), but with a lower TPD (thermal design power). Biostar lists the non-X models as each having a 65W TDP, down from 105W.
Lower clockspeeds for each chip support this notion. Biostar's listing pegged the Ryzen 9 3900 parts as each having a 3.1GHz base clock, a 700MHz reduction compared to the 3900X. There is no boost clock listed, though for reference, the 3900X tops out at 4.6GHz. If the 3900 does exist, it may still have high boost clocks, but the TDP means it would be less likely to sustain those clockspeeds under heavy workloads.
These would be interesting additions to the third-gen Ryzen lineup, particularly the regular 3900 (the Pro model would add security and enterprise features that are of little interest for a gaming or consumer build). In the 65W TDP arena, the 3900 would be going up against Intel's Core i9-9900, which is an 8-core/16-thread CPU priced at around $440 (street).
The 3900X is supposed to be a $499 CPU, though it's generally been marked up (way up in some cases) as AMD sorts through supply issues. If AMD releases non-X model, it would likely fall in the same price range as the i9-9900, and possibly compete with AMD's own Ryzen 7 3800X.
Since this isn't an official chip announcement, there's no word on when it might release. However, AMD recently said both its 3950X and third-gen Threadripper CPUs will arrive in November, so perhaps the 3900 will show up around then as well.
If it follows the pattern of previous AMD Ryzen CPUs, the 3900 might be the best overclocking option of the bunch. The 3900X already runs at close to maximum clockspeed, while the 3900 is likely to average much lower clocks due to its reduced TDP. Removing that TDP limit for overclocking purposes could net you a chip that performs as well as the 3900X, for less money.