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Old 22nd June 2011
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s2scott s2scott is offline
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Quote:
Originally Posted by mbw View Post
I am thinking that I will need to put a dual-port PCI-X 10gigE network card in there in order to bridge the 10gigE from the public
internet uplink in to the protected server room.

My question is this: Will the pci-X back plane be a bottleneck for achieving
line rate 10gigE ?
On a PCI-X based mobo, the only way you'll get close to 10Gb wire-speed throughput is to have two slots on two DIFFERENT and non-contended buses -- 10GB PCI-X NIC(1) on bus(1) and 10GB PCI-X NIC(2) on bus(2).

If you stay PCI-X ... seriously crack into your system's technical specifications. PCI-X is a linear bus; that is, cards on the same bus COMPETE with each other. If on the same bus, in a bridge mode, each 10GB card will CRUSH the other.

In all but the first-gen servers with PCI-X, the PCI-X chip set supports four (4) independent PCI-X buses. One bus (bus[0]) necessarily connects to the NORTH/SOUTH bridge for CPU and MEMORY access. The remaining three buses are typically spread to -- (a) bus[1] on-board chips (e.g. embedded SCSI controller, if it/they exists), and (b) the physical slots in the system.

If your PCI-X system includes legacy PCI-only slots, then one of these three buses is typically dedicated to these legacy PCI-only slots (bus[2]). Consequently, your PCI-X slots are typically spread over the remaining bus.

You need to crack your mobo's technical spec/documention an find those two independent and non-contended slots for your 10GB cards. If you can't isolate to slots, then don't even try.

IMO, though, if you need something approaching wire- (or glass-) speed, then go, go, go PCI-e.

The speed through all the rest of the system will be faster too. You can get a supermicro mobo with the needed x8 (or x4) PCI-e slots for sub-CAD$200, or a genuine intel mobo for just over CAD$200. Drop a low cost E3-1200 series XEON ($200) and you're smoking.

/S
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