Superfetch and Windows File Compression

Question

I've searched around for an answer to this question but haven't been able to find one:

If I mark a file for compression using the "Compress contents to save space" option that's in the file's properties dialog, if Superfetch loads the file into memory, does it keep the compressed version of the file in memory or does it first uncompress the file and then keep the uncompressed version in memory?

Answer 1

NTFS Compressed files are automatically uncompressed by the file system as they are accessed. Superfetch would see only the uncompressed file data and likely isn't even aware the file was compressed. For practical purposes the uncompressed file never existed in memory at all. Of course the uncompressed data would have been read into the file system buffers and may remain there for a time but these details are undocumented.