New GPU

I recentle bought a new 4070TI and it came with the 12+3 adapter, my old 3060 GPU was powered by just 1 PCIE and had a spare one not being use. I used both of this PCIE coming from the psu to power the 4070TI and it seems to work just fine but my question is "do i need the 3rd PCIE from the psu to the 12+3 adapater or should I just leave it like that?