I recently built a new setup (CPU: AMD Ryzen 7 1700 Motherboard: MSI X370 SLI Plus RAM: Corsair Vengeance LPX 16gb DDR4 @2133)
When I attempt to overclock it (even the slightest OC) will lock the multiplier to 15.5, cutting my performance in half of what it is on stock settings, is there something I do wrong or is this a bug in the system?
Any help/tips would be much appreciated
Try to flash latest beta bios from this thread: AM4 Release and BETA BIOS thread (UPDATE : 7-26-2017)
It's may help you with this issue.