CSI cameras: resource use vs. resolution scaling.

Hello all, I have a question regarding CSI cams and resolution.

I am wanting to run 3 CSI cameras simulataneously. I’ve been looking at camera kits from Leopard Imaging such as this one: https://www.leopardimaging.com/LI-JETSON-KIT-IMX377CS-X.html

I only need to capture images at 640x480 resolution. My question is, since the cost is the same for 3 cameras between the >4K, 4K, and 1080P cameras, does scaling down from a higher resolution consume more resources on the TX2? Would scaling down to 640x480 from a 4K source be more resource intensive than scaling down from a 1080P one? Or is the scaling performed on the camera prior to even reaching the TX2?

The reason I ask is because I would of course like to have the higher res sensors to play with for other things if at all possible :)

I believe downscaling is much simple work to make much different.