No it's not true.
Running a rom in clean mode, the save goes to the battery backed ram, which is written to the mem card on the next boot. (True clean mode, since the saver area doesn't need to be patched)
In Enhanced mode the save file is written direct to the mem card, and doesn't use the saver ram at all.
It also has 'Real Time SAving' (example...save in a middle of a jump) in enhanced mode if you wish to use it. This is also written direct to mem card.
So you have a choice of save modes, but at no time does the Scds-1 try and keep all it's saves in battery backed ram.... think about it, it would need a whopping bit a saver-ram to accomplish that.