Sorry to hear you're having difficulties.
I have not had trouble with PCI devices on any of the M5A97 series boards I've used, with one exception - an old SATA controller I had sitting around, which originally came free with a HDD I bought years ago. Pretty sure that was the controller's fault though, it was pretty much a POS.
Things to try/check -
- Update to the latest BIOS and reset the CMOS.
- From Linux, issue an lspci command to see if the card is being detected on the bus. If you're not sure how to find the device in question in the lspci output, do an lspci without the card inserted and save the output; then power down, insert the card, boot into Linux again, and compare the output of a new lspci command with the saved copy.
- In the Boot section of the BIOS, go to the CSM sub-menu and ensure that the Launch CSM module is set to Enabled. (This is a UEFI thing, it enables additional internal features of the BIOS making it behave more like a legacy-style BIOS with regards to device initialization. Bit of a long shot, but can't hurt to try.)
- For the ATA controllers, I have seen controllers which will not initialize if no devices are connected to it on power up, making it appear that the controller is not present. (That doesn't explain the TV tuner or NIC issues though.)
- Make sure you don't have a problem with a misaligned case preventing the cards from fully seating in the PCI slots.
- Make sure you don't have an extra motherboard standoff underneath the motherboard that is grounding something out.
If none of the above things pan out, it may be RMA time.