Intel Core i9 7900X is the latest model to feature a new cache architecture that Intel developed for the Knights micro architecture and Skylake server CPU models. The new Intel CPU cache architecture quadruples the size of L2 and makes L3 a non-inclusive cache. Intel did this for the sake of processing speed, but experts believe it will make exploitation of side-channel attacks a lot harder. Most side channel attacks are developed and usually deployed in cloud and hosting environments, where a side channel attack could allow an attacker access to troves of enterprise data stored in the cloud.
Source: https://www.bleepingcomputer.com/news/security/new-intel-cpu-cache-architecture-boosts-protection-against-side-channel-attacks/