Stock, these will overheat in the summer (ask me how I know

). At the very least you'll want to replace the thermal paste as already mentioned. However, to be honest your probably going to go down the route of custom cooling solutions if you end up catching the
bug. These open source mines are great for modding, and usually it results in spending too much money on them considering the astronomical odds of hitting a block. For example, I've got 3D printed custom stands, cooling fixtures.
Once you've got your cooling down though, they'll survive the summer and keep a decent efficiency in terms of consumption. I tend to under clock a lot of my hardware just for longevity though, which usually means you can get better efficiency also.