Movie Playback optimization

Hi guys,
For an installation I need to playback 23 videos @120 fps. I need to be able to dynamically change playback speed and I need to be able to play them backwards. At the moment I have a pretty slow ssd, so I run into problems. All videos are encoded in hap using adobe media encoder, i tested encoding in ffmpeg using its chunks option but i didn’t see much improvement.
My real question is: The wiki page, docs.derivative.ca/index.php?title=Hap on hap tells me how to calculate the bitrate i need for smooth hap playback.
In my case this would be 23 videos * resolutionX * resolutionY * 120 fps. Alright, so I can calculate what SSD will work with which resolution. But it seems playing the videos backwards needs a lot more SSD speed. How do I calculate what speed I need for backwards playing? How can I optimize this system for backwards playing?
Thanks a lot!

I’ll just place the link to an older answer I wrote about backwards movie playback, as the info is still valid afaik:

viewtopic.php?f=27&t=11087&p=42876&hilit=backwards#p42831