i have around 40 avi and wmv music video clips..that on total are around 13gb
if i use winrar to compress this large folder do you know how long it would take? and also will it make any diffrence in the size
Welcome to the forum
AVI are already compressed files, and there is no advantage in compressing them with RAR.
The compression speed is related on the CPU power and on the amount of RAM memory installed on your computer.