The amount of computing power on the network has grown exponentially this year, from 20 Terahashes per second on Jan. 1 to 3000 Terahashes per second today, Bitpay said.
The mining hardware also secures the bitcoin network, with each machine helping to verify the last transaction made. So more hardware helps make the network more secure.
Bitpay says it processed and cleared the $1 million transaction in a day. One benefit of the system, according to proponents, is that unlike credit card payments, bitcoin payments can't be reversed after they've been made.
Bitpay said last month that more than 10,000 merchants have signed up to accept bitcoins through its service.