By "thermal throttle", I assume you mean decreased Turbo Boost clocks. Real throttling happens when the card decreases it's clocks below its standard stock clocks as a safety measure to prevent damage to the GPU. Throttling will happen when your GPU hits it's thermal threshold, approximately 95c depending on the model.
Decreased Turbo Boost clocks happen when the card hits it's temperature target, called the Turbo Boost Temp Limit, as a part of normal operation. This is a user configurable setting and is usually set between 80c - 84c. For the GTX 1080 the target is set at 84c. This is user configurable, so you can set it at 70c, 80c, 90c, whatever suits your needs, but for overclocking you'll want to raise it.
The point is...