I have a roland A-70 w/ the jv-1 card, but I am also thinking of getting a A-90 w/ the jv-1 and the RD-1 cards (for the church I play for). My question is this if I buy this controller (A-90) how long will it take for the cards to load up.

I have the A90 with both VE-JV1 and VE-RD1.
The time to boot is very short (about 10 sec).
You have to consider the time to change boards. Open the door with screw driver, change the board and close the door again. This will take a time that makes impossible to be donne in stage from one music to the other. I'm trying to parallel these cards by a flat cable, with a switch to save time.

I thought there was a slot on the A-90 for the cards.

Maybe I will just buy it and midi them together,but I do play on buying a xp80 next.

Fernando let me know what you come up with.

Sorry for the delay on answering.
I was on vacation.
The A90 has a slot for a board, but just one. If you have two or more boards, you have to change it and boot again.
Take in consideration the VE-GSPRO. It has good pianos and synth sounds, with good polyphony.

But if I bought the A-90 how long will the booting process take

A few seconds only.