Yeah. I think Sony opted for a 1080P output for the UI, hence its much higher memory usage with less functionality.
But not everything will be 1080P as it's not necessary.
Microsoft managed to get background MP3 support, Voice Chat and so on all while gaming on a paltry 24MB of memory.
Allot of the extra memory usage in next-gen was as you said, video recording, image captures, suspend/resume functionality (Which goes straight to Ram) and caching.
Next-Gen all of that goes straight to disk and not Ram.
Straight to SSD can be good for low priority tasks and really great for suspend/resume and as a cache, compared to slower storage tech, and most surely is the best solution in next gen HD consoles, that must have a standard equipped mid-sized SSD anyway and find the right balance amongst components costs, but I guess that on PCs, that for their general purpose use often need a larger HDD anyway even when they use a fast, but small SDD for OS and selected tasks, spending little more than 50 euros to add 16GB instead of spending the same or probably more to get a large SSD instead of a small one can be an investment with better performance/cost ratio, not to mention that avoiding or reducing the need to swap thanks to larger RAM can make it acceptable to do it on the faster SSD instead of on the slower HDD withoud significantly shortening its life.
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