Z87 is the second PCIe slot 16x? (Single card)

[alcoholbob]

Are both the first and second PCIe slots on z87 boards 16x with only one card installed? I'm discovering that I can't install my gpu in the first slot if I put an aftermarket heatsink on due to the backplate protrusion. Thanks all!

 

[Insert_Nickname]

Usually not. Secondary PCIe x16 slots are usually only connected x8 physically. Unless you're using an LGA-2011 platform.

That said, performance wise there is very little difference between x16 and x8 PCIe 3.0. Something like 1-2%. So I wouldn't worry too much about it.

Some further reading over at guru3d.com:
http://www.guru3d.com/articles-pages/pci-express-scaling-game-performance-analysis-review,1.html