I would say it is not "useless" to buy 7700K without OC. 7700K base speed without OC is already at the max of 7700, which is 4.20. "K" does not mean you need to OC to get an advantage. Also, XMP profile is available way back to B250 mobo. So if OP do not want to OC, it is more sensible to get B250 with 7700K.