mac mini dropping gigabit connection

I presume you made sure ALL of your devices are gigabit?

Are all of the systems on the network gigabit?

...I have tried two different switches, a number of cables (including cat 6) all to no avail....

What make & model of switch? I've found that many of the low-end "consumer grade" gigabit switches (i.e.: 5-port "desktop" switch,) are often unreliable. I ended up getting a D-Link DGS-1016D 16-port switch, which was less than $200 at Office Depot and can be found for $120 at Amazon. While this switch is not that big, it is designed as a rack mount, so was intended for a "wiring closet" or server room. Thus the built-in fan, while not loud, is not something many people will want in their bedroom. But for me, it's better than the 3 Linksys, 2 Netgear and 3 D-Link "consumer grade" switches I've gone through prior to the DGS-1016D. My point is that you may have to start shopping on the "small business" part of the manufacturer's website, rather than the "home" sections.

The only other gigabit switch that has been reliable with my Macs (I'm also using a late 2009 Mini) is an Apple Airport Extreme (naturally. 😀 ) I've had that for over a year, just after I got the DGS-1016D. And while the Mac is not plugged into the Airport, a Windows Media Center is and I view the Media Center's DVR recordings on the Mac going through the DGS-1016D & Airport, which does tend to load the network so would make network performance issues more apparent, which I've not seen since I've gotten the DGS-1016D & Airport.

Do you have another device connecting to your network that isn't Gigabit? If a slower device is connecting to the network, the speed of the entire network will be reduced so it is compatible with the slower device. This might be the reason why your Mac keeps getting kicked off Gigabit.

tphc wrote:

thanks for the reply... what I don't understand is how my setup has worked flawlessly and as expected for 6 months and all of a sudden I'm back to the same issue before I had the logic board changed. The switch I am using is a belkin at the moment but also tried a netgear with the same problem still.

I don't have a specific answer for your situation. Perhaps you have bad luck with switches. Are the switches plugged into a UPS? "Consumer grade" switches come with those wall brick power adapters and those things are not the most reliable IMHO. I've had issues with switches and other devices where the power adapter didn't completely fail, but wasn't providing as much power (amperage) as it should so the devices was starved for power, and so became unreliable. 20 years ago, those wall bricks usually were around 0.2 amps. Stuff nowdays needs so much power, those brick are often in the 1-2 amp range, an increase by a factor of 10, which means a significant increase in heat. Heat is almost always bad for most electronics so I've had my suspicions that this is a factor in the seemingly shorter lifespan of these wall bricks. Thus the reason why I went with the DGS-1016D.

Recently there was a couple of really severe electrical storms in my area. It took out 2 of my UPS' and one of my PC's power supply that wasn't on a UPS. (Surge strip only, but that went bye-bye as well. 😟 ) There wasn't any obvious visual damage, so if I hadn't known there was an electrical storm, I wouldn't have made the connection. (i.e.: if I were on vacation away from home during the storm.) My point is that without a good quality surge protector or UPS, you could be getting affected by the quality of the electrical grid in your area, particularly with those wall bricks. (And as my example shows, even a surge strip is not a 100% guarantee.)

Very true. A power surge could have been sent through your network that way and may have semi-fried your Ethernet port. This is pretty unlikely, though. Try this: Go to System Preferences>Network, choose Ethernet, and click Advanced. Click the tab that says Ethernet, for Configure choose Manually and for Speed choose 1000baseT. Also make sure Duplex is set to Full-duplex and MTU is set to Standard (1500). I think you said you already had this, but I just want to make sure.

I've had te same issue. Mac mini 2010 connected alongside with a Mac Pro 2007 to a Netgear switch GS605 v2. The switch itself is connected to a router (Freebox V6) which has 4 ports. All configuration is on cat 5 cables.

A lead to the solution (unachieved) : when I unplug the Mac Pro from the switch, the Mac Mini gets gigabit connection (after restart, on automatic configuration in Network prefs pane). Otherwise it's impossible to have it work on gigabit ethernet.

Otherwise, when both are connected, only the Mac Pro gets gigabit and the Mac mini's stuck @ 100bt.

So the bug remains, just understood why though…

I'll add mine (a 2007 model mini, bought when the 2009 came out) to the list, a long list if you google a bit. Connecting at 100 base T manually works perfect, "automatic" never works.

There's no answer to the problem anywhere, and imho it's a hardware problem.

Personally I have only Apple network gear : a time capsule (latest generation) and an airport extreme (previous generation). With both I'm having the issue. Cabling is not the issue, tried all kinds.

I do have one question : my mini is still covered by Applecare (until April 2012 to be precise), and I'd like to get it resolved inside warranty, so did anyone have experience with Apple support over this issue ?