Look, I hate to throw shame in your game, but the fact is that most motherboards have a five year life expectancy. Sure, there are exceptions. Most motherboards have some kind of failure within five years though. That is a fact. So considering 3rd gen hardware hasn't been manufactured in any way, shape or form for at least 3 years, since about Q1 2014 when the board partners shifted operations to 4th gen LGA 1150 products, you can reasonably expect that even New old stock has been sitting on a shelf, aging it's capacitors and metal whiskering right along for about three years now.
Used stuff, even more so. Three years of usage, or even say, 1.5 years and the rest just sitting there doing nothing. That indicates that a significant portion of it's useful life is just, gone. Magnify that by the fact that you have abosolutely no idea what kind of abuse or environment it was subjected to, maybe living in a closed up cabinet with poor ventilation, a clogged CPU heatsink or dead fan, OR better yet, two years hammering away with a nice fat overclock, maybe with too much voltage, maybe not. Regardless, there are plenty of reasons why old hardware is a bad investment even for a garage machine, not least of which is the question of why you'd sink 250 bucks into something that's already seen 60% or more of it's useful life pass by when you could have a brand new system with a modest addition to that budget and then YOU get the full five or more years out of it.
None of which even considers the fact that anything 3-4 years old is not going to be able to perform on par with something just released this year. Even a 8th gen i3 will wallop a Sandy bridge i7 in almost everything. The ONLY exceptions being when there is really terrific support for threaded processing.
Just doesn't make sense unless you can get it for really cheap. I'm all for a 150 dollar Sandy or Ivy system with an i5 or i7, a decent motherboard and some kind of power supply that was either good for it's day or has been replaced with something worth having in there, but the chances of finding that are few and far between. For some reason, people think old hardware is worth a lot more than it is. Well, people who don't know better anyhow. Usually, those are the people selling that old hardware too. So good luck with that.