The new generation of consoles will bring big increases in CPU and GPU capabilities, but we get that with every new generation and it's no surprise when console chips get the same microarchitecture updates as the AMD CPUs and GPUs they're derived from. What's more special with this generation is the change to storage: the consoles are following in the footsteps of the PC market by switching from mechanical hard drives to solid state storage, but also going a step beyond the PC market to get the most benefit out of solid state storage.
It's about time. Solid state disks have become cheap enough that it doesn't make sense to not use them for gaming devices. Those who do have blazing fast SSDs don't see the full benefits yet because the game designers haven't pushed their requirements higher. That will change soon.
Microsoft and Sony are each using custom NVMe SSDs for their consoles, albeit with different definitions of "custom". Sony's solution aims for more than twice the performance of Microsoft's solution and is definitely more costly even though it will have the lower capacity. Broadly speaking, Sony's SSD will offer similar performance to the high-end PCIe 4.0 NVMe SSDs we expect to see on the retail market by the end of the year, while Microsoft's SSD is more comparable to entry-level NVMe drives. Both are a huge step forward from mechanical hard drives or even SATA SSDs.
The new XBOX will have a read speed of 2.4 GB/s. It's the slower one. Sony's PS5 will be at 5.5 GB/s. When dinosaurs roamed the Earth, I used floppy disks to store my word documents. It would take a few seconds to transfer the files over from my laptop. The total capacity of those disks was 1.44 MB. Now, we'll have media that can transfer an entire DVDs worth of data in one bloody second.
Eventually, PC gamers will also benefit as the new games will be designed to use the lightning speeds of NVMe SSDs. As the games can load GBs of data almost instantly, they should look absolutely stunning.