Upgrades are worthless (imho)
It was the great stuff at the beginning, but currently, with the current network hashrate is pointless...
you just get a few bucks (or cents) more ,for a 6 - 12 hours lapse, until all the network is updated to the latest version,
It's good to knock out CPU botnets.
And "next-gen" cards too (RX)..
Old tech from 2011 is getting better with every update.