What can I plug into a pcie 2.0 x16 slot?

[rilner]

Running a z97 Sabertooth Mark 2 (the one with usb 3.1).

There's a black slot at the bottom of that board, pcie 2.0 x16. The manual says it maxes out at x4 though, I don't understand what that means (3.0 x4 speeds?)

I want to use that slot for something, but I don't know what. Can I use a 3.0 x4 card without it being bottlenecked? I was looking at either a kc1000 ssd, an Asus usb type c card or else a TP-Link Archer T8E card (although I was going to use that last one in a x1 slot).

Could someone give me a clear rundown of each pcie revision comparatively? I'm just confused about bandwidth and such.

 

[achilles174]

It's physically a PCIe x16 slot but electrically an x4 slot and limited to PCIe 2.0 speeds. PCIe is backwards compatible so you can plug any PCIe, PCIe 2.0, or PCIe 3.0 card in there, whether it's x1, x4, x8, or x16.

If it's PCIe 2.0 or PCIe 3.0 it runs at PCIe 2.0 speeds. If it's x4, x8, or x16 it runs at x4. If it's PCIe 1.0 x1 or x4, it runs at full speed. If it's PCIe 2.0 x1 it also runs at full speed.

Typically that slot is connected to the PCH so it shouldn't steal lanes from your GPU. The slot is good for up to 2GB/s (16Gbps) so you could add a USB 3.1 Type C card (10Gbps). You'd actually stifle the SSD since it's PCIe 3.0 x4 this slot would run it at *half* the speed.

Assuming it's connected to the PCH, it would share lanes with the PCIe x1 slots on your board and it would also share bandwidth with some on-board components (eg, Ethernet).

 

[geofelt]

You can plug anything you want into that slot.

pcie 1/2/3 are forward and backward compatible; no issue there.

While the slot is full X16 length, the transfer speeds are limited by the chipset tp X 4.
That means you can get full speeds out of anything you insert except a graphics card which will run, but usually needs X8 fat least for best operation.

You could use most any pcie m.2 ssd device with a generic adapter like this:
https://www.newegg.com/Product/Product.aspx?Item=12K-017B-00001&cm_re=m2_pcie_ssd_adapter-_-12K-017B-00001-_-Product