PC won't boot with graphics card in the top PCI-E slot, but will in the bottom slot. Broken motherboard?

Er1kTheRed

Honorable
Oct 23, 2013
1
0
10,510
Hi all,

I have just assembled my new PC with the following setup:

Intel i5 4670k
ASUS Z87-C
Gigabyte HD7870
8GB Kingston HyperX RAM
120GB Kingston HyperX SSD
1TB WD Blue HDD
LG DVDRW
Thermaltake LitePower 600w Black Edition PSU
Windows 8.1

The PC will not boot when I place the graphics card in the top PCI-E slot. I get both the VGA LED and BOOT LED showing red and nothing happens. There is power to the GPU, as the fans are spinning. However, if I put the graphics card in the 2nd (bottom) PCI-E slot, the system boots fine.

I am concerned because the top slot is PCI-E 3.0 and the bottom is PCI-E 2.0 (both are x16 though), so this means the speed will not be as good? Also, I just bought it all and am wondering whether to return the motherboard back to the shop.

Any help you can offer would be much appreciated. I have spent 2 days trawling the web for answers but have not found a solution.

Thank you!
 
Solution
Try testing the board outside the case for ruling out a shortage.
If still the same, remove the CPU and check the socket for bent pins.