So there is a few things to note.
The Xsx CPU is 3.8Ghz in 8 Core with SMT disabled - that means only 8 cores 8 threads in this mode its 3.8Ghz it is 3.6Ghz in 8 cores 16 threads mode (SMT enabled)
From what we know so far the PS5 is always SMT enabled and always running with 8 Cores 16 Threads and at 3.5Ghz, that is quite literally just 100Mhz difference. If it drops by 2% thats 3.43GHz 170Mhz difference. The cpus are practically awash, if the PS5 is actually SMT enabled, DF believed this was the case.
From what I am seeing Xbox fans are taking absolute worst case scenarios for the PS5 (why the insistence of 9.2 TF ??) and taking absolute best case for xsx and using those numbers to prove a point and in so many ways performing mental gymnastics to produce the sums to satisfy their desire to prove the xsx is so much more powerful, its kind of disheartening / childish and where I was actually considering maybe this gen for the first time I might look at buying an xsx to not even consider it - I really don't like the behaviour from the xsx crowd.
Back to discussions about offloading the OS onto SSD instead of leaving it constantly in RAM.
My personal belief is I don't think Windows is capable of working that way - from what I understand xsx is using a modified windows10, but it is using the NT kernel, the NT Kernel is a lot bigger than the typical Unix / FreeBSD kernel and its not as efficient it was originally a microkernel design (which can be quite inefficient because of all of the context switching required) which for intents and purposes acts like a monolithic kernel, to get around a lot of the early antitrust law suits against MS, at 1 point MS even stuck internet explorer into ring0 of the kernel and said without it windows could not operate. I don't know how streamlined the win10 NT variant is compared to previous winNT kernels, but its always been a bit butchered (the original design done by VAX VMS designers was actually really elegant, but political company decisions butchered it)
FreeBSD Kernel on the other hand is Monolithic and its performant and its small. Most crucially everything above the kernel is modular, you can switch out the init system, the user interface, the services, anything after kernel, can be switched and swapped. Unix has a separation between User Interface and between Kernel. The Unix philosophy has always been that any service or application should do 1 thing and do that thing well, so there is clear separation between UI, between kernel etc, also the virtualisation tech in Unix (specifically Linux, I'm not sure about BSD here but BSD jails is old but very good and very fast) is more advanced than Microsoft's stuff.
Now this is not to say Microsoft cant do this, but in all likely hood they haven't designed XSX with offloading OS into SSD from RAM when in Game, if they had thought of this they would be shouting it from the roof tops, instead they clearly stated 2.5G is reserved for OS, so its obvious this thought never crossed their minds. Cerny on the other hand didn't even talk about reserved memory for OS. I think this is an ace they are holding up their sleeve, its something they must have thought about and the FreeBSD kernel design lends itself to this, its not too difficult to do this because the Kernel is compact that can remain memory resident and manage the hardware, while the UI side (the actual PS5 OS) can be switched in and out of RAM / SSD. How this will hit the wear and tear of the Drive I dont know, but its probably far less than you can think as they probably only need to push deltas through - why bother copying in and out the whole os, only copy back to SSD what state information has changed and this will probably be 100's of MB to SSD.
For Microsoft to do this, I reckon it would require quite a radical redesign in how windows 10 works. They have 8 months and this is software, its do-able and of course they can push system updates next year or the year after which does this, but I don't think they have done it, but also we don't know if the SSD solution they have in place will be good enough to do this. Also the split pool RAM is again another indicator that this strategy hadn't even crossed their minds. I almost guarantee they will do this and I bet in 4-5 years PCs will be doing this to granular levels such as suspending to SSD applications that have been minimised or that are not in the foreground, like I mentioned in my previous post, but right now I don't think they can.
Right now this is speculation, Sony haven't confirmed or denied this, but in a GDC presentation designed for Devs Surely they should have pointed out how much of that 16G would be reserved for system and how much would be available for Games Development, they held back this bit of information and I wonder if its because they were hoping no one would possibly pick up on this point and MS wouldn't have time to implement this solution before release. If I am wrong I sincerely apologise, if I'm right well done Sony / Cerny, really smart thinking, also well done NXGamer, its all originally from his video that this all clicked in. There is a few things that may make this not possible though, 1 thing is how do you do this with voice chat / part chat ? Or for example a separate music application like spotify running in the background.
The next thing I wanted to point out is about the ssd expansion slot. Microsoft have gone with a pretty elegant solution, the slot in custom SSD to gain extra storage - I initially thought this was the only solution, but I believe there is 1 TB internal, probably soldered onto the Motherboard and then you can buy extra space by buying these off the shelf custom ssd expansion cards. Its a really elegant solution, but also probably quite costly and they probably wont go down in price whatever MS retails the price at is what it will stay at as its custom (they can reduce it, but there is no competition for them to do so), possibly around $200 for a TB maybe? Its probably 1 way to claw back the loss per system they are willing to take.
The FUD I see is the PS5 solution, so basically what I've been seeing is people thinking the PS5 expansion would disable / remove the current internal 825 GB storage in the PS5, I think this is impossible that storage is most likely soldered on to the PS5 board as well, from what I understood that storage will always remain. More storage can in the future be added to an expansion slot, but its not a custom part it can be any SSD that meets the requirements of the PS5 and currently none exist (because its just too damn fast) and when they do exist probably by the end of this year, they will be incredibly expensive. I expect them to be around $400 - $500 for a 1TB drive, probably by mid next-year they will drop down in price and by the end of the ps5 generation they will be around $100 for a TB. This SSD solution Sony has developed, does not exist anywhere, I think people are overlooking this. It's a mistake I made in the initial reveal as well, I reckoned it was just them piggy backing on PCIE4 tech, without PCIE4 it wouldn't be possible, but the controller design is completely custom. It is something that just doesn't exist in the current hardware space.