Click to expand.The compression is automatic but MS do not specify the conditions in which it occurs. I upgraded 7 to 10 and Windows was compressed to 3.8 GB. I then did a clean install and it wasn't (so 19.8GB). Handbrake for mac 10.6 8. I then did an in place upgrade of 10 and again it was compressed (so back to 3.8 GB again).
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I think the compression only happens if the upgrade decides you have insufficient space on your SSD. It never happens if you have a HDD. I've not seen any performance issues using the compressed version and for bootcamp users with limited SSD space (like me) it is far better. The compression is automatic but MS do not specify the conditions in which it occurs. I upgraded 7 to 10 and Windows was compressed to 3.8 GB. I then did a clean install and it wasn't (so 19.8GB).
I then did an in place upgrade of 10 and again it was compressed (so back to 3.8 GB again). I think the compression only happens if the upgrade decides you have insufficient space on your SSD. It never happens if you have a HDD.
I've not seen any performance issues using the compressed version and for bootcamp users with limited SSD space (like me) it is far better.