Steem Power that you get from a post reward is based on the 3.5 day average Price of Steem in US Dollars.

I'll use curation as an example:

Curators get a maximum 25% of the post reward, paid out in steem power. So if a post payout shows $10.00, than 2.50 of that post payout goes to curators.

so the total curation payout would be 2.50 divided by the 3.5 day average price of Steem in US Dollars.

• If the price of Steem was worth $2.00, then 2.50 / 2.00 = 1.250 Steem Power paid out.
• If the price of Steem was worth $1.00, then 2.50 / 1.00 = 2.500 Steem Power paid out.
• If the price of Steem was worth 50 cents, then 2.50 / 0.50 = 5.000 Steem Power paid out.

So lower price of Steem means better Steem Power rewards for authors and upvoters.