The new ARM Cortex-A78C features support for up to eight big CPU cores. This allows for better multi-thread performance compared the the base A78, which only supports four big and four little cores. L3 cache memory has also been pushed up to 8MB. The company says this will further improve performance for workloads with large datasets. This applies to gaming as well, as the company claims.
Other improvements fall on the data and device security side of things. One feature ARM highlights is the Pointer Authentication (PAC), which reduces the number of exploits a device running this new CPU is vulnerable to. For now, ARM has not mentioned when we will see devices with the new Cortex-A78C CPUs. One of the earliest possible ones may be the upcoming Apple MacBooks, which are thought to be announced during the upcoming event on 10 November. It may take awhile after that before they hit the market. (Source: ARM)