When gpu's go through the roof again we will know a run is happening.
By the time GPU prices go through the roof the bull market will already be in full force. You need better indicators

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They seem to go hand in hand to me. I know if you wait for the Bull market it is too late. You will not get reasonably priced gpu's till the market cools.
GPU has been getting a big increase caused by the bullrun if crypto. A lot of miners are rushing crypto and that create a big noise in the miners. The only main thing waiting for the bullish trend of crypto to be happened again. But it may take a lot of time maybe after next bitcoin halving.