I'd post this on the official G.Skill support forums but I'm waiting for mod authorization to do so.
I just recorded a video of the Memtest errors I'm getting when trying to set my G.Skill Sniper F3-12800CL7D-8GBSR using a Gigabyte Z68XP-UD4 motherboard at its rated speeds, but I get errors every time I do. I use 7-8-7-24 at 1.6v and it fails. I explain more in the video and show what happens.
I'll try anything if I don't have to RMA these back to Newegg, because I think they're out of stock on these anyway.