Sure. Getting caught up in a rather pointless detail though.
You still seem super unaware of how Nanite works based on your latest posts to Bo. "That's an easy one Bo: Having them on RAM? What do you think games do when load a level? Fetch the data it needs to render to RAM and then render from there." That's not how engines build around streaming data work.. and absolutely not what the UE5 demo was doing.
It was using only a small portion of the RAM for a cache; there is no "entire level" loaded into memory. There is what is on screen + some cache.
The small cache is possible due to fast I/O. With slower I/O, you'd need a bigger cache.. thus have less memory available for what is on screen.
x = on screen data
o = cache
[xxxxxxxxoo]
[xxxxxoooo]
System with slower I/O has less x's, more o's, to compensate for it.
Here's Epic slide on how little memory is actually used for caching data: