Not getting Gigabit

[portreathbeach]

I have an iMac, macMini, macBook Pro and a Qnap NAS. They are all connected through a Netgear Gigabit switch, but my iMac will not connect at 1000Base, only 100. All the other stuff on the network works fine.

It isn't a cable issue, as the macMini is on a 25m run of cable and that works fine. I have tried different ports on the Netgear switch, but this doesn't make any difference either.

I have read of others with this problem, but there doesn't seem to be an answer. Does anyone have any experience with this problem, as copying 20+ GB of files between the iMac and the server takes ages.

 

[paduck]

Try connecting the Mac Mini and iMac to each other straight with a cable (no router) and see what sort of connection you get then. At least that will tell you if the Gig-E is working.

I know the Mac Mini is on a 25m cable run, but where is the iMac? Have you tried a different cable with it? Or put it at the end of the Mac Mini cable?

 

[tyche]

Have you tried swapping cables so the iMac uses one of the cables you know works at gigabit speed?

This wouldn't be the first time an Apple device didn't play properly with another vendor's hardware. Perhaps pick up another brand of gigabit switch to test connectivity.

 

[portreathbeach]

I've tried every combination possible. Different cables, different ports etc. I do get gigabit connection when connecting directly from iMac to macMini, so at least I know the iMac will do Gigabit!

But why will it not work through my switch?

 

[snberk103]

Do a Google search with iMac, Gigabit, Netgear....

I didn't have your model name - but just with those generic terms I came up with:

http://hintsforums.macworld.com/showthread.php?t=102481 (see last post, especially)

and

https://discussions.apple.com/thread/2037116?start=0&tstart=0

Also, I'm reading that Cat5e or Cat6 may be required.... that Cat5 often works, but not always.... so perhaps the iMac is just more picky?

Luck.

 

[paduck]

I've tried every combination possible. Different cables, different ports etc. I do get gigabit connection when connecting directly from iMac to macMini, so at least I know the iMac will do Gigabit!

But why will it not work through my switch?

I'd try getting a new Cat5e or even Cat6 cable and connecting directly to the switch to see if that works.

 

[geoffreak]

Keep in mind that most all consumer grade routers only get a fraction of the speeds they advertise. A "gigabit" router may actually only get 100-300mb/s in real world usage. If you really want to max out your cables (cat 5e or cat 6), you'll need an industrial/business grade router. You might also want to look for router benchmarks.

 

[derbothaus]

The problem is the item that does not negotiate correctly. Firmware issue with device or iMac. Try a good old PRAM zap. Do you get nothing when forcing 1000T?

 

[portreathbeach]

Done the PRAM thing, no go. Tried to force 1000Base T, no go. I am using cat6 throughout the installation. I get Gigabit when connected directly to MBP, but not to the Switch, in any port, even though those ports will allow Gigabit with MBP and macMini and Qnap NAS.

Loads of people have this problem when searching the internet, but there is no answer. I don't understand why the Netgear Gigabit Switch will work at 1000T with all the rest of my equipment, but not the iMac?