I'm sure someone will correct me if I'm wrong, but I think 'Rom Position Patch' will load the game into the Supercard RAM, rather than 'streaming' it from the SD card.
'Saver Patch' [set to 'DS Card'] - I think this writes the savegame to the DS cart rather than storing them on the CF/SD. So whatever original game you've got in your DS will have it's save overwritten with whatever ROM you load form the Supercard (providing the DS cart and ROM both use the same save type).
I think that's what they do anyway...
Yeah that's about it, needs some correction on the saver patch (er, i mean a bit more info to understand)
Rom Position Patch: When set to supercard it loads the rom first into the memory of the supercard, letting you play it back then like a normal cartridge based game
BUT this means Longer bootup time (it copies first the rom, then starts the game) Once ingame it should be equal to the other methode
When set to SD/CF it reads the data when t needs it from your storage device, means faster bootup)
Sometimes a game will not work when set to SD but will work when using the supercard option.
Saver Patch: When set to DS you need an original game in the ds with THE SAME SAVE SIZE/TYPE as the game you want to play.
This means, let's say, Nintendogs uses a 2Mbit FLASH save, this means you need an original game in the DS that also used 2Mbit FLASH in order to be able to save your game progress (This means your save on that card WILL be overwritten, be sure to make a backup of it with REIN R16)
Most roms do a check and give an error when a wrong ds cartridge is inserted, or the refuse to boot, some boot and let you play, but when it comes to saving it errors if the wrong save type is in the ds slot.
Now, we mostly will NOT need it cause most/all games save fine on SD/CF
It is usefull this option if you want to figure out a save type of a game, like i do to find out the save type for my compatibility list
Or if a new Save type comes out that the software does not support (but you can count on it that the software will be updated faster, then you can find an original gamecart that uses the new save type
)