Gpu core freq fluctuating when mining

Hi, today I got a 3060ti lhr ventus 2x OC and started mining RVN with Trex on Windows.

Current OC (afterburner):

• GPU +200 (900-1500mhz)
• Mem +100 (6900mhz)
• Pwr limir 79%
• Fan speed 70%
• Gpu temp 62ºC
• Gpu hot spot temp 77.6ºC

I noticed that the Gpu core freq fluctuates a lot, between 950mhz-1500mhz.

I'm averaging 24.5MH/s

I think that I'm little behind the normal mh/s for a 3060ti, but what is more concerning is the frequency fluctuation, any ideas?

EDIT: Increasing the PWR Limit to 90% corrected the fluctuation and put the CoreClock=1635mhz. However, the mining speed remains the same at 24.5MH/s.

What is going on..?