In an effort to make Project Scorpio games as mind-blowing as possible, Microsoft is giving developers even more access to the console's built-in hardware. Devs can harness the raw power of Project Scorpio's 6TFLOPs of compute power and 1172MHz of Polaris-derived GPU clock speeds, the custom 8-core x86 "Jaguar evolved" CPU, and 67% of the system's beefy 12GB of unified GDDR5 RAM to help optimize their games in a variety of different ways.
According to Digital Foundry's Richard Leadbetter, developers will have access to 67% of Project Scorpio's total unified RAM system memory, or 8GBs of Project Scorpio's total 12GB of GDDR5 RAM. For comparison's sake, devs only have access to 5GB of Xbox One's RAM, and the same amount on PS4 Pro. This extra 3GB of accessible memory is a tremendous advantage that can facilitate boosts across the board for a multitude of optimizations, including resolution enhancements, tighter frame rates, and dramatically faster loading times by treating the extra RAM as an IO cache.
Project Scorpio's system memory isn't just brawny, at 12GB of GDDR5 RAM, but also has the bandwidth to back it up. Scorpio's 12GB of GDDR5 RAM--made up of 12x 6.8GHz modules--is clocked at a respectable 326 GB/sec bandwidth speeds over a 384-bit bus. Remember Scorpio's memory is unified, not dedicated, so both video and system RAM are running through the bandwidth pipeline. But with all of these optimizations running in the background on the Scorpio Engine, combined with all of the APIs, scalers, and internal software tools, means the console's system memory reservation has increased as well. While devs have access to 8GB of RAM, the other 4GB is allocated for the operating system.