Question about program memory and installed program location

[datapusher]

When you install programs to the device, are you taking away from the devices ram? Meaning, I usually have around 15-20Mb of memory when my device is running. If Install programs to the device instqaed of installing them to the storage card, am I hurting ram?

If not, what would be the purpose of installing to the storage card over the device.

I have always installed programs to the storage card instead of the device in order to preserve ram. but I think that logic might be in error. I do however install today plugins like WP and UL and BS to the device. i do this so that it is not constantly accessing the storage card and draining thew battery.

is anything i said correct or am I way off base and how.

Thanks