RE: I continue to see the video card running at 8x instead of 16x even though everything says that max supported is 16x.
I have a couple of Jingsha X99 - which appears to be a derivative layout design from the common Chinese x79 knockoffs, including with m.2 support. I’m offering my comments as thoughts to help look at why your card comes up as x8 in an x16 slot. You are correct that you’re unlikely to see any real-world performance difference with it as an x8 vs. x16 (and this is pretty well documented observation).
I was interested in pcie bifurcation on the x99 board and learned some things that may apply in your situation. However these thoughts are all going to be dependent on the actual motherboard layout, BIOS, and then BIOS settings.
The BIOS probably has a ton of options that you may want to explore (if you have not already done so) esp related to PCIE lanes assigned, bifurcation etc. You can usually find these under the NB settings look for IIO0 or similar. you may also be able to find a screen showing what/how a card in a specific slot has linked up.
Noteworthy: silkscreen slot numbers on the motherboard bore NO relation to the PCIE slot numbering in the BIOS.
You’ve got x40 lanes of PCIE gen3 on the e5-2667.
Let’s add up the slots, x16, x16, x16 and x4 (m.2 nvme). that’s x52 lanes.
At least one of those slots on your motherboard is probably x8 in x16. Question is which one?
I’m ignoring the x1 slots (which I suspect are 2.0 and I didn’t investigate).
On my Jingsha x99 what I found is the following:
Numbering from the top (closest to ATX I/O ports) down.
#1 x16 in x16 and can be bifurcated up to x4x4x4x4 including x8x8
#2 x16 in x16 and can be bifurcated up to x4x4x4x4 including x8x8
–> #3 x8 in x16 and can be bifurcated up to x4x4
If I install an m.2 nvme drive in the m.2 motherboard slot then x4 lanes are robbed from slot #3.
In order to use slot #3 I had to force bifurcation to x4x4 and then I had a usable slot 3, without forcing bifurcation then slot 3 was not usable by any card, x4, x8 or x16.
(1) More than likely one of your slots is x8 in x16 and (2) more than likely using the motherboard’s m.2 slot will cause x4 lanes will get robbed from some slot. Two things to map out there.
I personally think these are really cool inexpensive boards (x79 and x99) with a lot of potential.
other thoughts, find a x1 video card, use that as the head on the MB and install qty 2 asus hyper quad m.2 for carrier, a x4 m.2 carrier card, and use the 1 onboard m.2 slot fora total of 10 high performance nvme disks. Or just one quad carrier and a nice graphics card and maybe a 10Gbe adapter in the remaining x4 slot… lots of interesting things to do here.