Update:
I tried DDU but nothing changed during the gpu-z render test, still x4 under load.
I ran heaven at 1080p, ultra quality, extreme tessellation, aa x8. Score 1400 with no OC. Does that seem ok?
Using HWiNFO64 sensors the pcie link speed is at 2.5 GT/s when idle and 5.0 GT/s when under load.