Well.

./python -m compileall $(find Lib -type f -name '*.py')
./python -O -m compileall $(find Lib -type f -name '*.py')

Tests:

FILES="$(find Lib -name '*.py' -o -name '*.py[co]')"
time 7z a -tzip -mx=0 python-0.zip $FILES >/dev/null
time 7z a -tzip python.zip $FILES >/dev/null
time 7z a -tzip -mx=9 python-9.zip $FILES >/dev/null
time 7z a -tzip -mm=bzip2 python-bzip2.zip $FILES >/dev/null
time 7z a -tzip -mm=bzip2 -mx=9 python-bzip2-9.zip $FILES >/dev/null
time 7z a -tzip -mm=lzma python-lzma.zip $FILES >/dev/null
time 7z a -tzip -mm=lzma -mx=9 python-lzma-9.zip $FILES >/dev/null
time 7z t python-0.zip >/dev/null
time 7z t python.zip >/dev/null
time 7z t python-9.zip >/dev/null
time 7z t python-bzip2.zip >/dev/null
time 7z t python-bzip2-9.zip >/dev/null
time 7z t python-lzma.zip >/dev/null
time 7z t python-lzma-9.zip >/dev/null
wc -c python*.zip

Results:

             pack  unpack   size
             time   time    (MB)
store         1.6    0.5    65.4
deflate        19    0.9    17.5
deflate-max   134    0.9    17.2
bzip2          21    4.2    16.5
bzip2-max     294    4.1    16.3
lzma          120    2.3    15.9
lzma-max      204    2.3    15.8

All numbers are about 3x larger. lzma-max is 8% less than deflate-max but 2.5 times slower. Bzip2 is out of the game.