update:
I have tested the Thermaltake LitePower 600W Black Edition in rendering and i also played a few games to stress both cpu+gpu. It did good, it seems that the psu is working fine. I didn't encounter any restarts or OS freezing. The cpu is the old FX 6350 3.9Ghz, the gpu is Gigabyte GTX 660 2GB GDDR5 192bit, 32GB DDR3 HyperX Savage 1600Mhz, 3x Seagate Barracuda HDDs, 4x Thermaltake 120mm coolers and Gigabyte 990FXA-UD3 mainboard.
Thank you.