10Gb NIC Question

[YAN]

I am trying to figure out the following.

The NC552SFP is listed as an eight lane (x8) PCI Express (PCIe) 10 Gigabit network card that can automatically auto-sense between x8 and x4 slots.

If I put it into an x4 slot will I still achieve 10Gb performance on both ports or will performance suffer?

If I can still achieve maximum performance on an x4 slot why is it an x8 card?

Thanks for any explanation.

[MUDBOY]

I am trying to figure out the following.

The NC552SFP is listed as an eight lane (x8) PCI Express (PCIe) 10 Gigabit network card that can automatically auto-sense between x8 and x4 slots.

If I put it into an x4 slot will I still achieve 10Gb performance on both ports or will performance suffer?

If I can still achieve maximum performance on an x4 slot why is it an x8 card?

Thanks for any explanation.

If you install it into a x4 slot, it will operate as x4 and I think the performance will a little suffer.

[HEUNG]

PCI-gen2 x4 lane has in theory 2000MB/s in throughput;

if you calculate 20Gb for the dual ported NIC (simplex) then you require 2.5GB/s (in theory).

Then you have consumed already all the performance of a X4 lane on PCI-Gen2;

and then we didn’t talked yet about the duplex traffic.

So yes you will suffer in performance if you put the card on a X4 slot (although it will work);

it might be all depending on the average utilization on both NIC ports if you will see it;

if you use both ports as active/passive (versus active/active) then then might not see the performance degradation.

Of course with PCI-gen3 (Gen8) the PCI-e gen2 speed went up from 5GT/s to 8GT/s so you would not suffer in performance with an X4 card on 10GB but we don’t offer any 10GB device in any way that do support PCI-e gen3;

those PCI-e gen3 cards will only be made for high performing video (NVIDEA) and 20/40Gb IB cards.

I hope this helps?