EDIT: The text has been adjusted to reflect that the chip was tested in a server platform.
A leaked Intel CPU has been discovered on the SiSoft database (opens in new tab). This CPU has six cores, Hyper-Threading, and was used in a server or workstation configuration with another identical six-core for a total of 12 cores and 24 threads. What's interesting, however, is that the amount of L2 cache per core has been increased from just 256 KB on Coffee Lake CPUs, like the Core i9-9900K, to 1.25 MB. This is even more cache per core than offered by the Core i9-10980XE (1 MB) and Ice Lake mobile CPUs (512 KB).
The amount of L2 cache per core is important to note because it has a big architectural impact on performance. This difference might be between two totally different architectures (AMD's Bulldozer vs. Zen), or between two architectures that share the same core but almost nothing else (Intel's Skylake vs. Skylake X). This CPU is very likely using one of Intel's new architectures designed for the 10nm node. But which architecture is used?
The most likely possibilities are that either this is a 10nm Ice Lake, Tiger Lake, or a 14nm Rocket Lake processor. There is little information on the latter two architectures, but one Tiger Lake leak revealed it has 1.25 MB of L2 cache per core (opens in new tab), just like this leaked CPU. That might be evidence that this is actually based on Tiger lake, but there has been no indication thus far that Tiger Lake will offer more than four cores, while Rocket Lake has been seen with eight cores (opens in new tab). This leaked CPU also has less L3 cache than the leaked Tiger Lake CPU; because L3 caches can be quite large, it makes sense that a CPU on a less-dense node would have less L3 cache than a CPU on a denser node.
Intel has already revealed it has the option of backporting architectures intended for 7nm onto the 10nm node (opens in new tab), so the possibility of Rocket Lake being a 14nm architecture with designs intended for 10nm CPUs is certainly there.
Given that the chips were tested in a server, that opens up the possibility that the chip is simply Ice Lake for server, which would have more L2 cache per core than Ice Lake for mobile (see Skylake vs. Skylake X).
Overall, it's hard to make any firm conclusions based on this result. The possibilities are many and the evidence is very thin. The one certainty is that this CPU is not a Skylake derivative. What isn't certain is whether or not this is 14nm Rocket Lake with a backported core, 10nm Tiger Lake, or something totally different, like Ice Lake for server.