Question will a USB 3.0 PCI card get throttled in any/all of these slots?

[kranky]

I have these PCI slots. If I get a USB 3.0 PCI card, will I get full USB 3.0 transfer speed in any of them, or will the PCI bus throttle the USB 3.0 speed?
- PCI Express 2.0 x16 (single at x16 or dual at x8/x8 mode)
- PCI Express 2.0 x16 (alt x4 mode, 2.5GT/s)
- PCI Express 2.0 x1 (2.5GT/s)

I just don't know how to calculate it. I'm trying to add USB 3.0 ports to an old rig. TIA.

 

[Tech Junky]

Looking at the 2 images below an X1 would be sufficient. Now, if you're USB card is a higher gen version it would need to be in one of the X16 slots or be bottlenecked by the bus speed.

 

[tcsenter]

PCI Express or legacy PCI card? USB controller cards are available in either. Even PCI would be able to handle ~110MBytes per second (effective). PCI Express 2.0 x1 is approx. 500MB/sec.

 

[kranky]

Thank you both!