Yes. And if you are using SimWardrobe's categorizer, then the algorithms are not compatible and it will not find your compressed downloads (not that I've ever actuaully tried it--second-hand knowledge for the win!).
Not strictly true--Categorizer finds most of my compressorized files, though it does appear to miss a few.
okay thanks.
i just compressorized my 5 gig downloads folder after deleting my cache files, and it added 4 minutes onto the total load time. replaced it with my old non-compressorized (trying saying that when you're drunk!)] folder and its back down to nine minutes..
Deleting the cache files will also slow things down the first time you run the game afterward, since it needs to rebuild the cache.