RSI of GDX is at 84, this is a very high level. The question is should we regard this as a sell signal (overbought) or not?

I believe it all comes down to the stage of the market.

Look at GDX chart over past 3 years and see what happened to GDX every time RSI got into overbought territory.  It was an immediate reversal every time

Several market analysts referred to the RSI of 70+ at the beginning of June as a sell signal, in hindsight that was not a good call, but from a trading perspective it was sound advice.

Everything changed however with the GDX breakout above 23.50 level and the corresponding high RSI readings.

If we are in a new gold bull market then the high RSI is indicative of a major change in trend rather than an overbought signal. (bull market behavior)

I believe this is the highest RSI in last 5 years or more. Even higher than in the 2016 GDX run from 12.40 – 31.79. It’s clearly bullish.

Looking at the 2016 bull run in GDX (breakout at 15 level), the high RSI reading at that breakout level was certainly NOT a sell signal as the market advanced another 6.5 months  afterwards.