People claiming "my PC works fine", yea uh, that's what I said about mine, the computer doesn't catch on fire when you start it with the PCIE card, it works, it just doesn't run as smooth as the PCI card. I tested both a Gigabyte Z77 UD5H, and an MSI Z87 G55, similar results on both.
You don't really need a PCI card to test it, just remove the PCIE sound card entirely and .reboot.
Every board probably reacts a little differently, but on the two boards I tested, I got the same results. The results are, inserting a PCIE sound card (Sound Blaster Z) caused noticeable difference in smoothness when dragging windows, more screen chop, laggier mouse movement, etc. Inserting the PCI sound card caused no noticeable change in anything.
I feel the PCIE sound card is interacting some way with the GPU that the PCI card doesn't. Either that, or the system gives way more priority to the PCIE card than PCI one.
This is Windows 7 btw. If someone else tests this, please don't come at me with some Windows 8 + vsync turned on + aero garbage for the love of god. It's pretty hard to notice things like chop with vsync permanently forced on in desktop mode. Win 8 even forces vsync on in borderless windowed mode, it's complete trash.
Edited by r0ach - 4/15/14 at 9:10pm