Hi, GOG Galaxy updating the witcher 3, the patch size is 640MB, I'm curious why 2 seperate patchs total only have 573MB (302MB + 271MB)? How come it can be 640MB? And 640MB is a patch 1.03 and 1.02 right?

Maybe some parts were changed in both patches.
When combining the patches, they won't include the obsolete version, updating straight to the most recent one - so that's why the combined patch might be smaller than the separate ones.

Is the update automatic? How can I check to see if I have it?

To the best of my knowledge...

Select the game in Galaxy. Next to the Buttons "Play" and "more" there should be an "installed" status, and just right of it a link for "changelog". click on "changelog" and look at the topmost entry. It starts with the version number installed.

Thanks for your feedback :)

Actually, the manual patches are smaller because they are compressed. The Galaxy download is bigger because the client downloads each patched file directly to the install folder.

It's installed. so I'm good. Thanks for your help!

I see. Thanks :)