Is this normal?

[N-drju]

I have just completed a GI cache file... it swelled to 4GB...

Is this a normal size for a render half the surface of which is covered in trees and grass? Whoa...

Any way to reduce it? Closing the render session as well as starting a render with this GI cache file is slow compared to what I'm used to. I guess high resolution plays a role here too.

[Matt]

That can be normal for a high res render if the vegetation is very "volumetric". Lower GI quality and/or GI cache detail will create smaller cache files. It could also be affected by the number of atmosphere samples.