@RatsInc_br I've never used T-Rex so this might be a shot in the dark but did you set an exception in your anti-virus software for your miner and run it with administrative privileges? If not, do so and then re-install the miner just in case your AV/anti-malware software has removed or quarantined certain components. Especially since the "--mt" line would modify your GPU performance through software.
I feel so stupid XD Problem was that I didn't run it with admin privileges. I though I did but... This helpped and now with first try I got 39 MH/s. Need to try another settings later. Thank you so much