to be honest I not sure how to explain . now we all mining ETH 1.0 , when next update 2.0 , it is auto convert or i need to sell before next update 2.0
You don't have to do anything.
Your 3 ETH will remain 3 ETH after the update.
It's just the upgrade of making Ethereum from being Proof of Work to Proof of Stake.
Thank you very much I feel comfortable now
1- When the Ethereum upgrade to Proof of stake , is cannot mine anymore with GPU ?
if yes cannot mine with gpu isn't better now try make big amount and hold it ?