I have also mined briefly and have written a guide on how you can start mining on Windows, it was one of my early posts here... :)
Just got back to check, it was my 10th Blog post, here it is if somebody is interested: https://steemit.com/steemit/@cryptos/getting-started-mining-steem-on-windows
in short, would it be worth mining with an i3?
Not sure at the moment, haven't mined for a while.
It won't hurt to try it and you should quickly see the results yourself, if you don't hit a block in a day at least, then maybe it won't be worth that much at the moment.
Well I'm more of a geek and I have a mining rig with GPUs which mine exp and the cpu (i7) mines steem and all that under ubuntu of course.
You are not the only miner around here, there are a lot of people coming from crypto mining or trading here... :D