I believe the Maximum Temperature for the 1500x is 95c. So running in the 70's c, from what I read, is considered to be within the CPU temperature range. Someone else I read was having similar temperatures. Then he removed the side panel to his computer case and the 1500X dropped from the high 70's c to the 60's c under load. Could also be dirty CPU cooler fins or you need to re-apply the CPU thermal paste again.
You might want to install Ryzen Master to adjust your CPU to run a little cooler. But someone else will need to instruct you on how to do it. Here is info about Ryzen Master: https://download.amd.com/documents/AMD-Ryzen-Processor-and-AMD-Ryzen-Master-Overclocking-Users-Guide... .
Found this link about the Temperature using the regular Wraith cooler that comes with 1500x:
Using AMD's stock coolers, the standard 1500X idled at 35 degrees and peaked at 68 degrees using the Wraith Spire. When overclocked to 3.95GHz, however, its temperatures increased to 42 degrees at idle and 88 degrees under load. That said, the heatsink wasn't uncomfortable to touch and while audible it wasn't screaming loud.
