XSX and PS5 SSDs, using the figures MS and Sony provide.
I believe the speed difference will be noticeable (loading, fast travel), but I don't believe it will allow for "entirely different looking open world games ". Not at all.
For one thing the raw speed difference probably isn't big enough. For another the frame to frame change in data required cannot typically be large relative to SSD speed, given the constraints on actually authoring assets, storing them, and that movement through the world is typically speed limited by gameplay.
Ah, still comparing both consoles I see. What's a lot more interesting to me is what is made possible moving from ~50MB/s to ~5.5GB/s. A 100X increase in IO throughput. There is a lot more this than meets the eyes here. Raw IO throughput isn't necessarily the game changer, it's the custom silicon for coherency (scrubber), mapping, file I/O, decompression (all of which is handled by the custom IO block) that makes the data coming from the SSD usable without reprocessing by the CPU. Without addressing these bottlenecks, the C/GPU would be locked up waiting/processing the data and you would see significant performance penalties when zipping data around at lightning fast speeds. In the end, you might end up with actual real-world raw throughput of ~2GB/s of the 5.5GB/s. (I'm making up that figure). Cerny has addressed all these bottlenecks and then some and the SSD has been central to his focus in designing the system and eliminating every conceivable bottleneck.
OK sure, XSX has a lot of these things too. Velocity engine, "Virtual Memory" (i.e. DirectStorage), hardware decompression... fine. I still think Cerny has architected a far more robust, efficient and effective system that is far more likely to reach its theoretical IO bandwidth limits. Yes, PS5 IO is
on-paper 129-367% the speed of XSX's IO, this is a fact, but for me, it's not at all the main bone of contention.
The main bone of contention is which set of 1st party developers are more likely to take advantage of the faster IO on their respective systems:
The system in which the whole system was engineered around this custom, super fast IO and the devs who have proven track records of handling exotic architectures (PS3 - CELL) and making them sing (PS4 - GPU Compute) and the whole wealth of development resources (SWWS) targetting just this one specific platform? (PS5)
or
The system that had an SSD dropped in at the last minute with a development infrastructure that also needs to support Xbox One, One S, One X, Lockhart, PC and xCloud, based on last-gen technology (PCIe 3.0) and pixiedust concepts lifted wholesale from their PC background. (Virtual RAM - LOL)
My biases are clear, and my opinion on which is the far superior system is clear, and I'm not even saying the XSX isn't capable of what the PS5 is capable of - it is, with the necessary sacrifices. All I'm saying is if one wants to experience what truly exploiting a super fast SSD in next generation game design actually feels, looks and plays like, beyond just faster loading... You're only going to get that on PS5. Take that to the bank.