Miner crashes at startup
Check Windows Defender exclusions, run as admin, update GPU drivers.
High rejected share rate
Try a different pool server (EU vs US), check your internet stability.
GPU overheating
Set a power limit (80% is a good start), improve case airflow, clean dust.
Low hashrate
Make sure you're using the right algorithm. Check if power limit is too aggressive.
Miner shows "GPU 0 " (blank) error
Use CUDA_VISIBLE_DEVICES=X to isolate problematic cards. Update drivers.