Still .. those are different ports .. does he uses any adapter?
Methinks we had a failure to communicate. PCI-e have two ways they are "measured". The physical length of the slot is measured by the number of lanes it is potentially able to support. The most common physical slot sizes seen are x1, which is that little stubby one, and x16, which is the full length one. However, not all full length PCI-e slots are able to run all of the signal lanes. Many are assigned only x8 or x4. Often, due to processor and other supporting chip limitations, some PCI-e slots are connected to the same source and share lanes.
For example, on my motherboard, there are two blue slots, two black slots and two white slots. All of them are full length but not all of them support the full 16 lanes. Each blue slot can run a maximum of 16x (also called 16 lanes). The black slots run at 8x and the white ones run at 4x, even though they are physically 16x long (yeah, I know, it's weird; I'll get into that in a moment). To further confuse the issue, each blue slot and the nearest black slot share the same 16x lane allocation. As long as only the blue slot is populated and its paired black slot is empty, the blue slot will be able to run at the full x16. But if I were to also plug something into the paired black slot, then both that black and the blue slot above it would run at only x8 each. Even if I plug a 16x capable graphics card into a blue slot and another in its nearest black slot, both will run at only 8x each. Oddly enough, the drop from 16x to 8x reduces performance by only a few percent, not half as one would think. That's why two graphics card running together can give much more performance than one by itself, despite running on half the lanes.
If only the black slot is populated, it is still limited by the motherboard to x8. The two white x4 slots will run at x4 no matter what is plugged in elsewhere up to a point. Motherboards have limits to the number of total lanes that can be used. Usually, that is determined by the type of CPU used. CPUs designed for the Z77 and Z87 boards, for example, are limited to 24 lanes. X79 boards can run up 40 lanes. Some boards can increase that amount by having an extra chip added to the board. On the flip side, some boards share PCI-e lanes with other functions on the board, such as additional SATA or USB ports. If those ports are activated and/or used, the PCI-e slot those ports are stealing lanes from will no longer work. If the PCI-e slot is activated, then those additional ports won't work.
One can use a freeway to describe how lanes work in a computer. A freeway may be wide enough for eight lanes but the traffic engineers may decide to paint only six lanes. This limits the amount of traffic that can flow through the freeway even though it physically has room for more.
In the case of the OP's card, it appears it is defective and is allowing only one lane of traffic to flow. To return to the freeway analogy, say there are 16 lanes of traffic on one side of a freeway (I know, some freeway!). An accident occurs that closes all but one of the lanes (two semi trucks tangled?). That is essentially what appears to have happened with the OP's card.
I hope this is a bit clearer than mud. It took me a while to grasp the concept.
