Poor PCI-E Bandwidth Performance

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I’ve recently got a 3090 and I’ve been running some benchmarks. The results are pretty good, but I’m concerned that some performance is being left on the table.


I’ve been running some 3D Mark bench marks and the PCI-E Bandwidth benchmark seems a bit off. It’s measuring in at about 6.4gbps where I’d expect it to be roughly double that.


It’s in the top PCI-E Gen 3 16x slot.


I’ve also got an Intel Optant pci-e hardrive further down in a 4x slot which I thought might be causing the issue. It’s the system drive, so I can’t just take it out to test.

So I have a few questions:


1) Is 6.4gbps a limiting speed for my set up

2) Do you think that the Optane drive is causing the issue and if not, what could it be?


Any advice on this would be appreciated.

More spec:
GPU: 3090
Motherboard: MSI MEG Z390 ACE (MS-7B12)
CPU: i9-9900K
System drive: 280 GB INTEL SSDPED1D280GA
Memmory: 64gb (4x16) Corsair DDR4 @ 2,144 MHz

 

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Thank you for your responses. The card is an MSI Suprim X btw.


The slot was indeed running at 8x and in fact I found there is a board inspector feature in the bios that lets you see what is plugged in and what it’s running at.


So, I decided to take out the optane drive and install Windows on an M.2 that was previously an empty scratch drive.


Running the benchmarks again, the GPU bandwidth bench did indeed (roughly) double.


However,


There was no significant gain for Timespy: 17412 > 17469


And a modest gain in port royal: 13234 > 13403


Do the scores seem a little under par for this set up at stock?