It’s a rare day that you’ll find a premium Evo-class 4K laptop on sale. And on sale for 55% off, saving you almost $1,000? Buy this Lenovo IdeaPad Slim 9i, now. Lenovo’s IdeaPad qualifies as an Evo-class laptop, which is part of Intel’s program for co-designing premium laptops hand-in-hand with the PC makers themselves. It’s a mark of quality, and we haven’t run into an Evo notebook we wouldn’t recommend. The kicker is that Evo-class laptops typically command premium prices, which can mean that we advise buying a cheaper laptop instead. Not in this case! Under the hood, this Lenovo IdeaPad Sli…