I also noticed the Dell Radeon R7 250 is using a PCIe 3.0 8x interface, but mine is stuck at PCIe 4x. Does anyone have one of these Dell R7 250's that they can load up GPU-Z and check their PCIe connection?

For anyone that sees this post, I have figured out the issue with my pcie lanes only running in 8x mode. I purchased a new cpu cooler and while I replacing the cooler I figured I would take a look at the pins under the cpu. Everything was fine, after re-seating the cpu and mounting the new new cooler when I loaded back into windows xp gpu-z reported the card was using pcie x16. It seems that the cpu getting re-seated made better contact on the pins and now everything is working like it should. Something to check if you find yourself in this situation.

There is a power saving feature called "Link State Power Management". Or what I tend to call PCI-Express Lane idling. Meaning that what you see in that GPU-Z field changes according to workload.

I once had a combination of Motherboard and Geforce GT 710 that did not quite work well in this regard. After a reboot/reset it would stick to idle lane config.