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I have an Asus M2N32 SLI deluxe motherboard with Gigabit Ethernet according to the specs. I'm running Windows 7, connecting to a Netgear WNDR3700 router (Gigabit capable). When I go into my speed / duplex settings for the card, the fastest it allows is 100 Mb/s. I have the latest drivers for the card. Why can't I set the card to run at full Gigabit speed ?

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Make sure you're using a CAT5e or CAT6 ethernet cable. – Ampersand Nov 22 '11 at 16:05
I have to question whether you really have the latest drivers for the Ethernet on the motherboard. If it is gigabit capable, you should be able to select it from the dropdown list. – LunaMezza Dec 9 '14 at 18:36
@Ampersand Already done, using CAT6 for the connection between my machine and the wall, CAT5e everywhere else. (I know using CAT6 won't make anything faster when everything else is CAT5e, I'm just describing the actual physical layout) – Alex Marshall Dec 9 '14 at 18:48
Sure there is no semantic error involved 1000 Mbit/s vs. 100 MB/s? – bummi Dec 9 '14 at 18:55
@bummi Gigabit speed is 1000 Mbit/s. What part of this conversation is ambiguous and makes you think there's any confusion over what Gigabit speed is ? 'Gigabit speed' is certainly not 100 Mbit/s – Alex Marshall Dec 9 '14 at 19:59

You can - just do nothing special at start and allow "Auto-Selection". If NetGear have gigabit , you'll see link negotiation at 1Gb (which doesn't mean you have automagically real 1Gbps speed also, but it's different and next theme)

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I've already gone into the settings and auto-selection doesn't negotiate the link at 1 Gbps – Alex Marshall Nov 30 '11 at 18:30
You have to verify all 3 points of failure (changing on e in one step): router interface, cable, NIC. Note of Ampersand is valid in extending to the max possible area – Lazy Badger Dec 1 '11 at 17:38

Both the network interface in your computer and the interface on the router must support 1000Mbps. I suspect that whatever machine you're using only support 10/100 modes and not full 1000Mbps.

That router definitely does, so you'll need to look at the specs for the motherboard you're using to validate that it also supports 1000Mbps. Most products for home and small business users support auto-negotiation and have had 1000Mbps links for some time.

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I've already verified that the motherboard supports 1 Gpbs speeds, and that I'm using Cat5e for the entire connection path to the router. – Alex Marshall Nov 30 '11 at 18:31

You do not say if you have other computers wired to your router, but assuming you do, if all the devices on your wired network are not capable of gigabit Ethernet then it is possible you will not be able to use gigabit Ethernet on any of your devices. For instance, if you have a gigabit Ethernet router with two gigabit Ethernet capable computers attached to it and one computer that is not capable of gigabit Ethernet, none of the devices will operate at gigabit speeds because the network speed would be set to the fastest speed of the slowest device. Some modern routers can bypass this requirement, but I'm not sure if yours does or not. To eliminate the chance that this is your problem test your connection speed with only gigabit Ethernet devices running on the network and see what happens.

Also, make sure your cable is gigabit Ethernet compliant.


May 2005

If your switch supports only gigabit, then you will have to convert every machine that’s connected to that switch simultaneously, which could lead to a significant amount of down time during the transition.

March 2011

All gigabit ethernet components are backwards-compatible with typical ethernet, so you don’t need to buy all of the following parts at once. However, you won’t get the maximum speed on your network until all the essential parts are gigabit-ethernet compatible.

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Are you sure this is still true for switched Ethernet? AFAIK, the "slowest device" limit only applies to dumb hubs. – grawity Nov 22 '11 at 9:03
@grawity - Heterogeneous links (presence of) still lead to a some degradation rate for pure Gb-pairs, to varying degrees for different equipment and not to a large extent – Lazy Badger Nov 22 '11 at 9:24
I cannot speak for every device, though this is what I have always been taught. I did actually test this a less than a year ago with a DIR-825. It would not connect at gigabit speeds when a non-gigabit device was attached. Although that was only one specific instance, I believe it is the norm. – ubiquibacon Nov 22 '11 at 9:59
@typoknig - As I understand it, "essential parts" only refer to the path between two communicating computers -- NIC, cable, switch, cable, NIC. The presence of other computers is only relevant when connected to a simple hub, but bridged and switched networks can handle different speeds just fine due to isolation of the physical layer (according to this article). – grawity Nov 25 '11 at 16:29
@typoknig - The first article you linked to says "If your switch supports only gigabit," which seems nonsense to me -- Gigabit should be backwards-compatible with Fast Ethernet; in other words, "1000" and "10/100/1000" should mean the same thing in product catalogs, despite what the article says. (I couldn't find any sources on that, though, so I may be wrong. But your own second quote claims compatibility.) – grawity Nov 25 '11 at 16:39

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