Where do current gen systems store their temp. video capture?

As the title says, I'm wondering where the current systems store the temporary video they always capture. 15min for the PS4, 5 min on Xbox One and about half a minute on the Xbox One X (I think this can be changed).

Maybe I'm searching the wrong phrases but I haven't been able to find anything that explains where this video is being stored. My guess is that it's stored somewhere other than the harddrive as the constant writing would be a hindrance to the loadtimes.

Is it stored temporarily in part of the systems RAM? Or other chips on the motherboard?

It's common knowledge that the PS4 Pro has 8GB RAM + an additional 512mb, but accordring to the iFixit PS4 Pro teardown the Pro has 2x 512mb DDR3 chips:
https://www.ifixit.com/Teardown/PlayStation+4+Pro+Teardown/72946
Is this where the video is stored on the Pro?

 

it real time stream encode to HDD / https

 

Are you sure about that? That seems like a pretty insane way of doing it. Limiting the read speed of the HDD for a feature that only few will use.

It would also mean that installing an SSD in the system would kill it rather quickly since it would write to it constantly. Something I’ve never heard mentioned when people were benchmarking loadtests with different types of harddrives.

 

For the PS4 it has a separate chip that always runs and encodes video. This includes recording crashes so you can see the last few seconds of what happened.
It's always active and always encoding, but it's a totally separate video encoding chip as to not affect performance. The way it runs games also makes it somewhat okay to do this as well so keep that in mind. Had it been the PS3, nah this wouldn't ever work.

Xbox One I'm not sure.

 

That’s what I thought. But does it write to the Harddrive at all times or is it kept and refreshed inside that chip (or nearby flash)?