Power issues with new SFP NIC

Wardy125 · December 10, 2019

I've just purchased a Chelsio N320E 10G SFP card, which is a PCIe 8x card.

I'm currently using an MSI z87-G45 mobo, with dual GTX 1080s in SLI.

MSI says my board's PCIe setup is: Gen3 (16,0,0), (8,8,0), (8,4,4), which to my understanding means that currently, the two GPUs are running at 8x, which is fine - it works great.

Now, when I plugged the NIC into the last port, my pc refused to even start. The lights came on, but I didn't even get a post screen.

I've been messing around with combinations of the cards, and it seems that the following is true:

Will boot with just the NIC, and onboard graphics
Will not boot with 1x GPU and the NIC in the second or third slot
Will boot with the NIC in the top slot, and 1x GPU, but I get blue screens and kernel power errors.

The last point is what's messing me up here, the card works fine without any GPUs, and I don't get any blue screens, so I don't believe it's faulty.

And I'm using a 1000w power supply, so I really don't think it's under powered? Especially considering the thing can run dual 1080s no problem (the NIC draws 14W according to the website).

Am I missing something obvious here?

I have no idea what's going wrong.

mariushm · December 10, 2019

As far as I know, SLI requires a minimum of 8 pci-e lanes to work.

So if you use all 3 slots, you'll disable the SLI, because one card will run at pci-e x8 and the other two slots with be pci-e x4.

Check if you have the latest bios, update if not.

The BIOS may have some quirks about mixing video card with non-video cards in the pci-e x16 slots.

Note that the network card will most likely work in pci-e x1 slot, if you use a pci-e riser cable/adapter.

If it's pci-e 3.0 slots, each slot gives you a maximum theoretical speed of 970 MB/s, so a sustained 900 MB/s is doable , good enough (considering 10g is 1250 MB/s)

You can buy low profile brackets which will probably be compatible with your card, here's a couple examples:

https://www.ebay.com/itm/New-Low-Profile-Bracket-10Gb-2-Port-B/133165684163

https://www.ebay.com/itm/Low-profile-Bracket-for-DELL-W1GCR-HN10N-Broadcom-BCM57810S-DP-10Gb-BASE-T/183037579217