PS5 has the raw SSD speed advantage, I'm not nearly as willing to give them the implementation advantage just yet. Microsoft is doing some work around the usage of that SSD that are very impressive and that I feel many aren't appreciating. They've created a new I/O system specifically for gaming, they've designed a technique with custom texture filter hardware (not standard in RDNA2) around better utilization of textures of and physical RAM, the SSD is used like virtual RAM with 100GB instantly accessible by developers, they created a new compression systems specifically for gpu textures.
Moving on, they are far from limited to just 10GB. It's 13.5GB available to games. People are treating RAM as if everything is 100% dedicated to graphics processing. It isn't. Not every part of a game requires the highest speed access to memory. Many parts of a game that go into RAM on these consoles will also be the basic stuff that just makes the title work outside of just graphics processing. The gameplay systems, animations, enemy behaviors, combat mechanics and systems etc etc. And, again, Sampler Feedback Streaming for the visual part of titles literally changes the dynamic of how textures are loaded into memory. For games that utilize it, and I'm sure it will be more as time goes on, only the specific sections of a texture that's actually visible in the game will ever actually be loaded into physical RAM. So traditionally if 4GB or 6GB worth of RAM would be filled up with textures, Xbox Series X with SFS (Sampler Feedback Streaming) has the ability to cut that potential memory usage down to 2GB and 3GB respectively. As Microsoft said, it leads to a 2-3x multiplier in how physical RAM is used. In other words, Xbox Series X will have no issue with RAM, and there are games right out the gate at launch that will prove just that.
People think that it's the launch games that will be the easiest on the platform and the later titles where the memory setup will prove to be an issue? Wrong. Any issue, if any exists, will be on earlier titles since they won't necessarily all be designed to take advantage of SFS unless Microsoft somehow finds a way to make it automatic without developers having to code or modify their engine for it. The Xbox RAM setup is far from "not ideal." Any apparent issue is oversold on that front. Xbox will have absolutely no limitation for games this gen in that area. People who believe there will be an issue don't understand how it will actually work for devs. Am I saying that I do? Nope. But I know enough to know that people are going to be disappointed if they actually think this is going to hold Xbox Series X back in any meaningful way.
Take a PC title like Assassin's Creed Odyssey. It goes up to 6GB of VRAM usage at 4K at max quality settings. Gears 5 was hitting north of 5GB at 4K ultra quality on PC, and that is one of the most impressive titles on PC out there.
Here are some more examples.
How much VRAM do you need when anti-aliasing is applied at 1080p, 1440p and 4K?
www.tweaktown.com
Far Cry 4 4K Ultra with AA enabled 5.7GB VRAM
Witcher 3 4K Ultra with AA 3.2GB VRAM
Battlefield 4 4K Ultra with AA 2.9GB VRAM
Shadow of Mordor 4K Ultra with AA 5.4GB VRAM
GTA5 4K Ultra with AA 6.3GB VRAM
Some of these games are older, but don't think for a second that they didn't bring it on texture quality on their PC versions. We will only now be approaching what some of these older PC games did with VRAM on PC with these consoles. It's why I cited Assassin's Creed Odyssey in there, to reference a newer game. And the VRAM needs haven't changed drastically in newer titles. In fact, in specific cases, the texture usage is down on some more impressive titles. . Even the Resident Evil remakes VRAM requirements, while high, are exaggerated.