Turbografx!

[A Black Falcon]

Speaking of, I hate Turbografx saving.  The internal capacitor lasts a couple of weeks tops.  There's eternal devices I can plug in to add more storage, each with their own strengths and weaknesses, but they all have similar issues with how long they last.

I've had a Turbografx CD base unit since 2009, which is where the save chip is, and I've never lost a save file. I have lost save files for other systems in that time (N64 Controller Paks, I'm looking at you... stupid awful things!), but not the TG16.  And I doubt that I've made sure to turn the system on every two weeks for that entire time.  I mean, it's possible I have, but ... I'm not sure about that.  This has led me to  wonder if it's somehow actually powering the capacitor and its SRAM chip while it's off so long as you keep the system plugged in.  I definitely keep it plugged in all the time. (If it's not drawing power while off, I've been amazingly lucky...)

I also have never lost a file in my Memory Base 128.  This is the save backup unit which plugs in through the controller port.  A few dozen games support it directly, but for others you have to make backups of the internal memory with specific games, and switch the blocks back and forth through those games.  It's not the most convenient system but it works and has a lot of storage.  It uses 4 AA batteries to hold the saves, but it clearly also uses power from the system because I've never seen the low battery light come on while the thing is plugged in to the system.  If I remove the batteries, the low battery light stays off... until I unplug it, when it turns on immediately.  (It has a capacitor to hold the saves for like a half hour or something while you switch the batteries.)  So yeah, it's clearly getting power from the system.

I have quite intentionally never stress-tested how long exactly these can last while not plugged in, I don't want to lose my saves. :)

Ultimately, I may apply a mod to replace the SRAM chip with another chip that permanently saves the data, as well as using an additional modern fan-made device to swap files in and out of that very small storage space.

Despite my good experiences with TG16 saving, both of these things you mention are very interesting indeed... is that a FeRAM swap or something, for the first one?  And what's that second option?  I definitely haven't heard of it.