Intel's 11th Generation Rocket Lake processors aren't due until March 30. However, some retailers are already shipping out orders. One user from the Chiphell forums has gotten his hands on a retail Core i7-11700K, and it would appear that Intel is using a similar memory overclocking concept as AMD's Infinity Fabric Clock (FCLK), but with Rocket Lake chips.
If you're not familiar with AMD's Ryzen processors, many of which sit on our best CPUs list, the FCLK dictates the frequency of the Infinity Fabric, which serves as an interconnect across the chiplets. Adjusting this value allows you to hit higher memory frequency overclocks. By default, the FCLK is synchronized with the unified memory controller clock (UCLK) and memory clock (MEMCLK). Obviously, you can run the FCLK in asynchronous mode, but doing so will induce a latency penalty that negatively impacts performance.
Since Rocket Lake isn't officially out yet, we're not completely sure how Intel's portrayal of the FCLK memory overclocking will work. The BIOS screenshot shows two operational modes for the CPU IMC (integrated memory controller) and the DRAM clock on MSI's Z490I Unify. Apparently, Gear 1 runs both in a 1:1 ratio, while Gear 2 puts them in a 1/2:1 ratio. It's similar to how the FCLK works on Ryzen processors.
According to the author of the forum post, his retail Core i7-11700K seems to hit a wall at DDR4-3733, suggesting that DDR4-3733 is the limit at which Rocket Lake's IMC can run in a 1:1 ratio with the memory clock. In retrospect, the majority of AMD's Zen 2 processors scale to a 1,800 FCLK (DDR4-3600) with some samples hitting a 1,900 MHz FCLK (DDR4-3800). If Rocket Lake has the same limits, it's going to lose points since AMD's latest Zen 3 processors have peaked as high as a 2,000 MHz FCLK (DDR4-4000) before breaking synchronous operation.
