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GA-X79-UD7 slow LAN


Intel NIC slow WAN download on 1.0Gbps, but ok on 100 Mbps

This is my first Intel NIC. It's the 82579V Gigabyte Network Connection and I've installed the v.16.5 driver off the Intel website.

Upon fresh Windows7 X64 install, internet was running about half speed. I dig around a little and find it speeds up to normal if I set the adapters link speed to 100mbps.

What's up with that???

I know it's not the router, other computers hooked to the same router run normal and I swapped the cat5 connections around to verify.


Running the internet with the NIC set @100mbps is fine, the problem is that my gigabit LAN is slowed to that 100mbps setting.

The only thing that seems different is the Intel vs Marvel onboard NIC's.


So, is it some obscure setting? I have the latest drivers installed, this is all new soft/hard ware.
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Here's my system: Twitter

Top Deck Station * Enermax MaxRevo 1350W PSU * Gigabyte GA-X79-UD7 * Intel Intel Core i7-3960X * Corsair H100 * Corsair 32GB 1866MHz * 2 120GB Vertex3 Max IOPS SSDs in RAID0 * 2 750GB Western Digital Caviar Blacks in RAID1 * Plextor PX-LB950SA for a burner * LG UH12LS28 drive for a reader * MSI N560GTX-Ti Twin Frozr II w/2GB DDR5 running dual ASUS VW266H 25.5" widescreens * DTV/DSL Internet connection at 10 meg per/sec down and 768K per/sec up
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I've just got a GA-X79-UD5 (Intel 82579V NIC) and I've got the EXACT same issue.

My internet line is 120mbit/s downstream and I'm noticing the following :

Auto negotiate (which negotiates 1gbit/s, correct) gives me very bad performance (50-70mbit/s from WAN).

Force 100mbit/s full duplex gives me full 100mbit/s performance (100mbit/s from WAN).

I first thought it was my ISP but I still had my old system running next to it which downloads at 120mbit/s (1gbit/s full duplex auto negotiate).

The issue remains when using 16.7 or 16.8 drivers (and if your problem is the same as mine, I'm pretty sure I can add 16.5 in there as well).

I'm going to use a Ubuntu livecd now to see if that helps.

Hope someone can find a fix for this or I'll be forced to RMA the board.


I've just tried out Ubuntu and the problem is exactly the same.

Either the kernel in Ubuntu has the same issue as the windows drivers, the problem lies in the option rom of the bios, the problem lies in the way Gigabyte put the chip in their boards or something wrong with the Intel 82579V iteself.

Either way I'm stuck

Here's the link to the relevant issue on the Gigabyte forums :

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My LAN/WAN NIC issues are fixed!

I Just flashed the latest Beta Bios - f7 and now I can use 1.0 Gbps Full Duplex at full speed on the WAN and LAN both.

I'm also using the 16.8 Intel NIC driver.

mb_bios_x79-ud7_f7 can be found here.

v16.8 Intel NIC driver can be found here.

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