"AMD Ryzen 7 1700 Overclocked To 4GHz On All 8 Cores – Provides 1800X+ Performance With Decent Motherboards & Cooling"
"What will be really interesting is to see how far the 1800X can be pushed using air cooling.
The 8-core chip has a base clock of 3.6GHz with a boost to 4GHz, so we can realistically hope for around 4.4GHz with air cooling, depending on the exact cooling solution and, of course, the CPU lottery (there are always slight variances when it comes to overclocking tolerances with processors, and you just have to hope you get lucky).
At any rate, 4.4GHz will be plenty enough for some storming performance levels."
http://wccftech.com/amd-ryzen-7-1700-overclocked-4ghz/