Area-51 R2, CPU-Z, GPU-Z, Core Temp, SpeedFan

CPU-Z and GPU-Z are great for showing you data about your hardware.

Referring to the above snapshot of GPU-Z, my Area-51 R2 shipped with the Titan X in the top PCI-Express x16 slot (SLOT1). See how GPU-Z reported it as =
PCIe x16 3.0 @ x8 1.1

I moved the Titan X into the middle PCI-Express x16 slot (SLOT3). Now, see how GPU-Z reports it as =
PCIe x16 3.0 @ x16 1.1

PCI-Express x16 slot (SLOT1) = Gen 3, running at x16 bus speed (x8 if Intel i7-5820K CPU is installed)
PCI-Express x1 slot (SLOT2) = running at x1 bus speed
PCI-Express x16 slot (SLOT3) = Gen 3, running at x16 bus speed
PCI-Express x4 slot (SLOT4) = Gen 2, running at x4 bus speed
PCI-Express x16 slot (SLOT5) = Gen 3, running at x16 bus speed (x8 if Intel i7-5820K CPU is selected) (NVME SSD + PCIe adapter = Boot drive)

Adding the free Core Temp and SpeedFan screenshot:

My 5 year old OEM GTX Titan X (12GB, pascal) versus RTX video cards =

75% slower than RTX 3090
73% slower than RTX 3080 Ti
52% slower than RTX 3080
40% slower than RTX Titan
24% slower than RTX 3070 Ti
13% slower than RTX 3070
2% faster than RTX 3060 Ti
37% faster than RTX 3060