There are no 3rd Gen AMD Ryzen X470 Drivers & Support | AMD chipset drivers for W7 yet (and I am afraid there will never be one). You should be fine with the 2600 though. I am having the same dilema, either wait for something with uncertain prospects or switch to Linux (once the rdrand/systemd issue will settle down).
Edit: I've created a ticket for AMD to get the information, whether they do plan to release (at all) chipset driver for 3rd Gen Ryzens, similar to what they did to 2nd Gen. I will post the reply here, unless somebody from AMD will decide to comment.