Older Intel 10GBaseT (82598EB, E10G41AT2) at PCIe Gen 2 x4?

[mattlach]

Hey all,

I am planning a 10Gig update to a computer I don't have local access to, so I have to get my ducks in a row before I drive out and set things up.

I happen to have a few older single port 10GBaseT adapters using Intels 82598EC chipset on E10G41AT2 cards. These cards are PCIe Gen 2 compatible x8 cards.

I guess my question is, has anyone run these in a Gen 2 x4 slot?

Gen 2 has a bandwidth specification of 500MB/s per lane. So x4 is 2,000MB/s, or 16,000Mbit/s, which is more than 10Gbit/s by a healthy margin.

In theory it SHOULD be enough PCIe bandwidth to support a single port 10 gig NIC.

But does it work in practice? Has anyone tried it?

 

[tinfoil3d]

I have x550t running on x1(limited by hardware due to lack of free lanes) pcie2 lane having 415 mbyte/s max speed. Definitely would work for you on x4.

 

[mattlach]

I have x550t running on x1(limited by hardware due to lack of free lanes) pcie2 lane having 415 mbyte/s max speed. Definitely would work for you on x4.

Appreciate the input! I will post back here with my experiences when I get out there.

 

[JSchuricht]

I have some x520 cards running in x4 slots , cards are gen 2. No issues with bandwidth on them.

 

[mattlach]

I have some x520 cards running in x4 slots , cards are gen 2. No issues with bandwidth on them.

Turns out this is not the case with the older Intel 10gig copper NIC's. The architecture must be very different.

Starving them of the full 8x lanes resulted in very spurious behavior, with occasional disconnects. Downstream speeds were OK, but upstream were very poor. It's almost as if they assigned upstream and downstream bandwidth to specific PCIe lanes or something like that, which really makes no sense since PCI Express is full duplex.

Either way, fiigured I'd update for everyones benefit, if anyone else has these. The cards work great at their full number of PCIe lanes, but with anything less, they act up.