Thanks for joining the Desktop Board community.
It appears to be an issue with compatibility. I have checked video cards specifications, the R9 270x is PCI express version 3.0. The motherboard is PCI Express 2.0 and if the new card does not work it may be that this is down clocking to version 2.1. Or, there is a possibility that you need higher power supply.
My PSU is seasonic 500w and its fit the recommendation of the card, so i don't think that the problem is here.
What did you mean when you wrote " down clocking to version 2.1"?
The version of the PCI Express slot. In this case your motherboard supports 2.0 and your video card 3.0, some of the video cards can down clock the version of the PCI Express revision. But as I mentioned, this might be a compatibility issue because your old video card is working properly.
The card is fully compatible with pcie 2.
So I think it's something with the board!
Maybe there is some BIOS update that I need to install?