Like supernova1138 mentioned, aside from a couple rare cases the only i5's with ht are the mobile lineup for laptops and the ones with ht are dual cores so more similar to desktop i3's. Sandy bridge, ivy bridge, haswell, haswell refresh, devil's canyon, broadwell and skylake are all straight quad cores for the i5 and hyperthreaded quad cores for the i7's. Depending what you do depends how useful hyperthreading is or isn't. So far the initial skylakes being released are the i5 6600k and i7 6700k with no mention of the 2c/4t i3's which may come later. Haven't heard much about i3's for skylake but haven't heard any news that they're ending the i3 line either. It's a bit backwards this time, usually they release the lower clocked/locked core cpus first then release the unlocked performance chips later. With skylake they opted to release the unlocked chips first. Efficiency and performance are up a bit but so far overclocking results look very similar to devil's canyon.