Fee problems(the fee is mined in the first hour of mining):

mine 1 hour and quit: fee 12%
mine 2 hours and quit: fee 11%
mine 3 hours and quit: fee 10%
mine 4 hours and quit: fee 9%
mine 3 hours and quit: fee 8%
mine 12 hours and quit: fee 1%
...

So if your rig is unstable and crash, restart every hour, 12% fee...


Gpu search high intensity problems

1. Searching 500 000 solutions in a low difficulty. 17 solutions found. spminer will only report 2 of them.
2. Searching 500 000 solutions and the pool change difficulty and reject your work.(stale share) you loose 500khash
3. Searching 500 000 solutions and the pool change block and reject your work. you loose 500khash
3. Searching 500 000 solutions and the pool restart your work. you loose 500khash (nicehash does this all the time)