The files I place on the compressed drive are only compressed from 1.15MB to 1.14MB, is it normal this should be only 100KB of compression per MB?

Compression on NTFS uses modified LZ77 algorithm. It is very fast but not always effective.

If works pretty well for the files/documents containing a number of repeating sequences of symbols. Example of such files types: text files, RTF, BMP, HTML files, etc...

For other file types, such as binaries, GIF, JPG, ZIP files, etc. this compression algorithm is not useful so that these files might not be compressed at all.