Update 9/27 @ 5:10pm: Added a link to Anandtech's discussion of Bristol Ridge. It was mentioned in the post, but I forgot to add the link itself when I transfered it to the site. The text is the same, though.
While Zen is nearing release, AMD has launched the AM4 platform with updated APUs. They will be based on an updated Excavator architecture, which we discussed during the Carrizo launch in mid-2015. Carrizo came about when AMD decided to focus heavily on the 15W and 35W power targets, giving the best possible experience for that huge market of laptops, in the tasks that those devices usually encounter, such as light gaming and media consumption.
Image Credit: NAMEGT via HWBot
Bristol Ridge, instead, focuses on the 35W and 65W thermal points. This will be targeted more at OEMs who want to release higher-performance products in the holiday time-frame, although consumers can purchase it directly, according to Anandtech, later in the year. I'm guessing it won't be pushed too heavily to DIY users, though, because they know that those users know Zen is coming.
It turns out that overclockers already have their hands on it, though, and it seems to take a fairly high frequency. NAMEGT, from South Korea, uploaded a CPU-Z screenshot to HWBot that shows the 28nm, quad-core part clocked at 4.8 GHz. The included images claim that this was achieved on air, using AMD's new stock “Wraith” cooler.