MebiuW, a forum user at Weibo.com, posted what appears to be an internal document from Intel that showcases the performance of the unreleased ten-core Core i9-10900K. We have been expecting this part for some time, but Intel has been totally silent on their upcoming 10th-Gen Comet Lake parts. According to this purportedly leaked document, the 10900K is up to 30% faster than the i9-9900K in threaded workloads, but the operative word here is "up to."
This document includes SYSmark, SPEC, XPRT, and Cinebench benchmarks, and with the exception of Cinebench, most of these benchmarks are quite kind to Intel and are used quite frequently in Intel's internal benchmarks. That 30% performance bump comes from the SPEC benchmark, and Cinebench R15 results are just behind it with a 26% increase. Given that the 10900K is a ten-core CPU and the 9900K is only an eight core, it isn't surprising that we're seeing this kind of performance.
Other benchmarks show a much lower improvement, especially XPRT which averages about 3-4% higher on the 10900K than the 9900K. This benchmark measures single-threaded performance, and since we know the architecture isn't really that different than its predecessor, it's almost certain that Intel has yet again increased clock speeds with this upcoming 10th-Gen chip. The aging 14nm process has shown surprising gains in clock speed, but this certainly is coming at the cost of power; we can see that under multi-threaded workloads, the performance bump is only equal to as many cores Intel has added to the 10900K, indicating that Intel hasn't made very much, if any, gain on core clock speeds.
It's noteworthy that the test results peg the 10900K at a 125W TDP, but also lists a 250W TDP. The second value should represent the chips' PL2 power state that's required to hit all-core boost clock rates.
Also, there is a little footnote that says this might not reflect all of the latest security updates which do decrease performance on Intel CPUs, but given that this is being compared to another Intel CPU, that's probably not a big deal.
Overall, we can clearly see an increase in performance coming with the 10th-Gen chips, but Ryzen 3000 still offers tough competition with much higher multi-threaded performance and competitive (but slightly weaker) single threaded performance. Given that these projections appear in what are purportedly Intel's own performance docs, the 10th-Gen chips will need a good price to stand out.