-will increase the time needed to rebuild the WIM,unless the WIM is uncompressed,
-but it may result in a better compression ratio if wimlib can do a better job
-than the program that wrote the original file. A side effect of this is that
-every stream in the original WIM will be checksummed, so this can help verify
-that the WIM is intact (equivalent to applying all the images from it).
+will increase the time needed to rebuild the WIM, unless the WIM is
+uncompressed, but it may result in a better compression ratio if wimlib can do a
+better job than the program that wrote the original file. A side effect of this
+is that every stream in the original WIM will be checksummed, so this can help
+verify that the WIM is intact (equivalent to applying all the images from it).
+
+Note: as mentioned in the README, wimlib generally provides a slightly better
+XPRESS compression ratio than Microsoft's software, while it generally provides
+a slightly worse LZX compression ratio than Microsoft's software. So, you may
+not want to specify \fB--recompress\fR when optimizing a LZX-compressed WIM
+created on Windows with Microsoft's ImageX.
+.TP
+\fB--threads\fR=\fINUM_THREADS\fR
+Number of threads to use for compressing data. Default: autodetect (number of
+processors). This parameter is only meaningful when \fB--recompress\fR is also
+specified.