They sometimes hit 4.0-4.1 on a single core, so when you fire most of the new games it will drop to 100- 200 Mhz up from base speed when more cores are in use.
For me personally i think it is worth investing in better motherboard if you plan to stick with the build for a longer time and since Ryzen will have probably 2 more upgrades on this socket getting good mobo now is wise choice, so something like this.
PCPartPicker part list /
Price breakdown by merchant
CPU: AMD - Ryzen 7 1700 3.0GHz 8-Core Processor ($308.98 @ NCIX US)
Motherboard: Asus - PRIME X370-PRO ATX AM4 Motherboard ($149.49 @ SuperBiiz)
Memory: G.Skill - Ripjaws V Series 16GB (2 x 8GB) DDR4-3000 Memory ($159.99 @ Newegg)
Total: $618.46
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-05-16 05:07 EDT-0400
You can stick with stock cooler for time being until more coolers that support AM4 socket comes out so you have more choice in both cooling and esthetics, also stock cooler comes with nice LED RGB Ring what looks nice if you have see through side panel.