Question GPU Voltage drops while gaming

[bode4k]

Grettings. I`m using lenovo legion Y540-17IRH . And I have problem in games, after few minutes of gaming, gpu volatge starts to regulary drop to 0.6 from 1, causing huge fps drops. GPU&CPU is not overheating, temperatures not goes up 55. Temperature limit is set on 87. Also, processor was randomly locking (again, with normal temp) hz to 0.79, but I fixed it with throttlestop by disabling BT Prochot. I have latest possible BIOS and drivers. Please, help . My GPU is geforce gtx 1660Ti. Please. help me with solving this problem.