The difference is in concentration of the active compound Salvinorin A.
1gram 5X extract is equivalent to 5 grams of raw leaf
1grams 80X extract is equivalent to 80 grams of raw leaf
The way extract is made, the Salvinorin A from 5 grams of leaf is extracted and deposited on 1 gram of fresh leaf, and so you get 1gram of 5X, in other words, one gram of leaf, with the Salvinorin A concentration of 5 grams.
This makes it easier to use, because you don’t have to puff your way through 5grams of leaf, you just do that one gram.
The problem is that a lot of these companies aren’t actually giving you an 80X extract. Anything above 40-60X is basically impossible to tell the difference – you just black out – so they can call it 200X for marketing purposes, but you’re not going to know the difference.
Also, don’t fall into the "bigger is better" trap. Just cause there IS a 40X doesn’t mean you will enjoy it more than a 10X. It depends on your personal situation and level of experience. Don’t be a hero, or an idiot.
Here’s what BlackHatBotanicals.com says…
http://blackhatbotanicals.com/faq.html#productinfo
"I’ve never tried Salvia. What would you recommend?
From customer feedback, 10x or 20x extract is considered the best place to start for newbies. Return customers may prefer to order stronger extract and use less product. Higher strength extracts are not only more cost effective, but also allow customers to enjoy the full potential of the product with ease. However, we strongly urge our customers to practice common sense, have a sitter present, etc."