Saturn Battery

After I replied to that battery post, I turned on my Saturn, to my surprise, it looked like the battery was dead, meaning I had lost all of my game data.. (specifically Panzer Dragoon Saga!!!) so I booted to the dashboard thing, (sorry.. X-box term) and looked at the memory manager.. all my games are still there.

I turned it off, then on again, just now. (about 20 seconds later) Same thing. Asks me to set my clock, language, etc, but all my game saves were there.

What exactly does this mean? I know Im gonna need to backup my games soon. I thought that once the battery went, all memory went as well. In fact, Ive had a few saturns like that.. Since the battery was dead, it lost all save games a few seconds after being shut off... any info on this?
Possibly there is just enough charge left in the battery to maintain the save-ram, but it is not enought to keep the clock ticking. If this is the case, don't expect your save games to last more than a few more days...