What you're asking is simply impossible. Not impossible as in you have a too slow computer - that can be solved with money. It's impossible as in physically impossible. You can't do what you ask.
Your charset has 83 characters. There's 83^20 20-character strings that can be formed from this. That's about 2.5*10^38, or incidentally approximately 2^127.5.
If you create one billion (10^9) 20-character strings per second, you'll spend over 10^20 years generating the 20-character strings. And you haven't yet started your 19-character strings - which is not a trivial problem either.
The universe is 10^10 years old. So generating the 20-character strings, if you have extremely fast storage, able to swallow 20 billion bytes per second, it would still take 10^10 times longer than the current age of the universe.
For those 10^20 years, you're filling a 10TB hard drive every 8 minutes. Currently they cost around 250USD a piece, so just storing this (if hard drives were that fast...) would cost you in the neighbourhood of 450000USD - per day. You'd probably call Seagate or someone and ask for a good bulk rate at that point, of course, explaining that you plan to keep on purchasing at that rate for as long as they are able to deliver.
When you're nearly finished, in around 10^19 years, you'll probably have some issues with the planning authorities - because the hard drives now equal the earth in mass, and lead to weird gravitational distortions.
83^20 is incidentally very close to 2^128, so pages such as this may be worth a read as well.
This is of course back of the napkin-math. It may be off by a order or three of magnitude - but that's irrelevant. The numbers show that your biggest worry is simply the heat death of the universe, not how fast your CPU is.