DANO_2 :
So recently my GPU has been doing a weird thing where the fans do not go full speed under load. However, if I move the GPU power connector slightly, my GPU fans work like normal again. I have already tried MSI afterburner and Radeon Wattman but still, nothing works. I have an Rx 580 8gb V1 and I've had it for 3 months with no issues till now. Any ideas as to how to fix this? I think the PCIe power cable might be bad, but one of my friends thinks it could be bad soldering in my GPU.
That does sound like a loose connection at the PCIE power cable. You can switch to another PCIE power cable from the power supply. If the power supply is modular, then you will need the another PCIE cable from your PSU supplies (depending upon the PSU it may be in a Velcro bag or from the box it came in). If it isn't modular the other connector will be in the wad of cables within the PC.
Some lower watt power supplies may only have one PCIE power cable, in which case you would need to contact PSU manufacturer for replacement.