Why does base64-encoded data compress so poorly?

Question

I was recently compressing some files, and I noticed that base64-encoded data seems to compress really bad. Here is one example:

• Original file: 429,7 M

Answer 1

It's not Base64. its them memory requirements of libraries "The presets 7-9 are like the preset 6 but use bigger dictionaries and have higher compressor and decompressor memory requirements."https://tukaani.org/xz/xz-javadoc/org/tukaani/xz/LZMA2Options.html