M1015 in ASUS P5K PCIE x16 slot

[PsiCzar]

My unraid server has an ASUS P5K motherboard. I recently bought an M1015 card to provide more SATA ports and when I went to install it in the PCIE x16 slot a red light lit up next to the slot. I didnt try to power on the server, I immediately took the card out and installed it in the PCIE x8 slot where it is running perfectly

 

Should I assume from the info above that my board will only accept video cards in the x16 slot? Is there something in the BIOS that I can change? I had always planned to install 2 M1015 cards at some point but it doesn't look that will be a possibility with this board.

 

For future reference is there anything in the motherboard specs that would indicate if a x16 slot is compatible other non-video cards?

[sacretagent]

i am using a P5B motherboard and had a BR10i running in that pcie x16 slot

i just changed the relevant bios settings and it worked great... once i buy a bigger case i will probablyput also a m1015 in that slot

 

[BetaQuasi]

For future reference is there anything in the motherboard specs that would indicate if a x16 slot is compatible other non-video cards?

 

Unfortunately, manufacturers of consumer motherboards rarely, if ever, document this.