Ethermine many stare share!

[Pippuz96]

Hi everyone this is my rig:

Intel Celeron G1840
8gb ram
AMD Sapphire nitro + RX570 Blockchain driver and bios modded
PSU Corsair hx1200i

i'm using ethermine with asian server since i live in south korea. It seems that every hour i have so many stare share but i dont understand why, also my average hashrate its always lower than the reported one ( the rig is running already from a week with some restart of few seconds )

Should i change pool or settings?

Thanks