samer.forums :
He can save $100 by going i3 and still get the same performance of the older gen i5 ... and put that on the motherboard.
But what's the point? The "upgrade" is still a quad-core CPU that isn't going to offer any noticeable improvement. The OP is throwing their money away.
samer.forums :
later on he will be able to upgrade ti i7 8700K as he wishes and sell the i3 ..
Or he could take an i7-6700 right now.
samer.forums :
upgrading to 4 cores i7 today is not a good idea ..
But you've recommended that the OP upgrades to an i3-8350K?!
samer.forums :
better either he upgrades to Gen8 or keep his pc as is until the right time comes for his big upgrade.
Again, the OP can upgrade to an i7 right now and be done with it. No new motherboard, no second copy of Windows, no mucking about selling old parts. Not only is it the easiest option, it's also the cheapest.