HWinfo64 showing PSU 12v but when i playing Voltage going to down (Please Help!)

Why a vote?

It's typical for many if not most PSU to drop +12V some as it becomes heavily loaded with something like a GPU during gaming.
There must be something wrong .. 1.9 V instead of 12V :oops:

  • Unplug card and put it back ("refresh" electronic contacts?)
  • Generate a logfile (GPU-Z can create logfiles too). With logfile we can compare voltage in idle and heavy loads ... PCIe Slot voltage and 12V voltage
As Tom already said, it's normal for the +12V rail to drop under load.
The +1.9V PCIe Slot Voltage reported by GPU-Z seems to be a wrong value. Check in HWiNFO what it shows under "GPU Rail Voltages".