I found out my problem, so I will leave this here in case anyone else has the same issue.
I ran HWiNFO64 on my windows and I found out that my 10GbE card is using PCIe 3.0 x4 correctly.
I checked my unraid server and it turns out that the slot I had the card in was a PCIe 2.0.
Here is how I found out.
Open a terminal and type "lspci | grep Ethernet", that will give you a list of devices. Copy the number at the beginning for the device you are trying to get detailed info for.
Run the following. Replace 06:00.0 with the numbers for yours.
sudo lspci -vv -s 06:00.0 | grep "LnkSta:"
This is the result I got.
LnkSta: Speed 5GT/s (downgraded), Width x4 (ok)
I was expecting Speed 8GT/s for PCIe 3.0. I double checked my MB manual and yep it's a 2.0 slot.