The provided solution for the 980X is OK for stock (including turbo) speeds. When you ratchet up the VCORE, VTT, and speed north of 4GHz, do expect to see scary temperatures indeed! I can keep mine at 1.325V 4.4GHz under 80C on the H70 (LinX 0.6.4) whereas not changing any setting and mounting the stock cooler three cores were over 100C in under two minutes. With the fan on HIGH!
The temperature increased VERY rapidly indicating the heat output of the overclocked CPU "swamped" the capacity of the heatpipe cooler. This was sitting horizontal on a bench. Mounted in a case it would be even worse.
If you can get the H70 do so! It's a good little cooler.