copy pasting from an earlier post : MS's SSD isn't designed to have instantaneous seek time
[I'm just gunna quote from the DF article how most everything you said is wrong, and bracket in my anecdotes.]
[NVME SSDs all have virtually no seek times. I think it is actually none on some newer ones. Seek times like described in the PS5 deep dive, are the read head literally moving on A HDD, which an SSD obvi doesn't have]
that ps5 gets thanks to its dedicated DMAC (that has the power of 1 or 2 Zen2 cores) and the I/O coprocessors.
The final component in the triumvirate is an extension to DirectX - DirectStorage - a necessary upgrade bearing in mind that existing file I/O protocols are knocking on for 30 years old, and in their current form would require two Zen CPU cores simply to cover the overhead, which DirectStorage reduces to just one tenth of single core.
"Plus it has other benefits," enthuses Andrew Goossen. "It's less latent and it saves a ton of CPU. With the best competitive solution, we found doing decompression software to match the SSD rate would have consumed three Zen 2 CPU cores. When you add in the IO CPU overhead, that's another two cores. So the resulting workload would have completely consumed five Zen 2 CPU cores when now it only takes a tenth of a CPU core. "
Then the ps5 has more than twice Xbox's bandwidth,
[This is True!]
add to that the compression system (KRAKEN) that gives 9 GB/s throughput post compression and it creates an immense difference.
It's a system that Microsoft calls the Velocity Architecture and the SSD itself is just one part of the system.
"Our second component is a high-speed hardware decompression block that can deliver over 6GB/s," reveals Andrew Goossen. "This is a dedicated silicon block that offloads decompression work from the CPU and is matched to the SSD so that decompression is never a bottleneck. The decompression hardware supports Zlib for general data and a new compression [system] called BCPack that is tailored to the GPU textures that typically comprise the vast majority of a game's package size."
Xbox's SSD is just not designed to work like the ps5's ssd to create a revolutionary shift in game data access.
The form factor is cute, the 2.4GB/s of guaranteed throughput is impressive, but it's the software APIs and custom hardware built into the SoC that deliver what Microsoft believes to be a revolution - a new way of using storage to augment memory (an area where no platform holder will be able to deliver a more traditional generational leap). The idea, in basic terms at least, is pretty straightforward - the game package that sits on storage essentially becomes extended memory, allowing 100GB of game assets stored on the SSD to be instantly accessible by the developer.
A technique called Sampler Feedback Streaming - SFS - was built to more closely marry the memory demands of the GPU, intelligently loading in the texture mip data that's actually required with the guarantee of a lower quality mip available if the higher quality version isn't readily available, stopping GPU stalls and frame-time spikes. Bespoke hardware within the GPU is available to smooth the transition between mips, on the off-chance that the higher quality texture arrives a frame or two later. Microsoft considers these aspects of the Velocity Architecture to be a genuine game-changer, adding a multiplier to how physical memory is utilised.
The Velocity Architecture also facilitates another feature that sounds impressive on paper but is even more remarkable when you actually see it play out on the actual console. Quick Resume effectively allows users to cycle between saved game states, with just a few seconds' loading - you can see it in action in the video above. When you leave a game, system RAM is cached off to SSD and when you access another title, its cache is then restored. From the perspective of the game itself, it has no real idea what is happening in the background - it simply thinks that the user has pressed the guide button and the game can resume as per normal.
[XSX is clearly using the SSD to change how it does many things. It honestly sounds a lot like what Sony is doing, just slower. And then you have the multi game suspend/resume, which Sony have made no mention of. All in all, the primary differentiation here is speed alone]