I was wondering how it would effect an SSD if this was checked:
I was just curious whether it would save my SSD disk space?
By enabling drive compression you would save space on your hard drive, however the benefit is not without cost. Compression uses processing power (CPU). Every time you access a file, it has to be read and uncompressed to be worked with. Every file you save or edit will also have to be compressed.
Whole disk compression is not a good method for growing storage, adding another hard drive or upgrading to a larger drive is a better choice.
Not that whole disk compression is bad, there are definite advantages in the right situations. However, "what if" is not one of them.
Only add the NTFS compression to Files and folders where you read the data most of the time. DON'T ENABLE it for folders where you write data very often. With information being compressed on the fly, you're consuming more of an SSD's available write cycles than if you were writing the files uncompressed. This could have negative implications on the drive's endurance.