: walter biscardi's Blog
: Apple i5 and i7 27" iMacs do NOT support high speed ethernet transfer
SEE UPDATES BELOW, I've updated this story twice since the original entry.
We took delivery of the brand spankin' new 27" i7 iMac last week and connected it immediately to our Final Share SAN in about 5 minutes for video editing. Quick tests showed the SAN was connected and working fine.
Then today I started really editing on it and I'm dropping frames every 10 to 30 seconds. Now it appears the ethernet controller that is in the new Mac cannot support the speeds necessary to edit video via the SAN. Our 2 year old iMacs can, but the brand spanking new, most powerful iMac cannot.
I'm at a loss as to how Apple can improve every aspect of this machine, including the absolutely stunning 27" LED backlit display, but then cut back on something as simple as an Ethernet Controller that should be designed to work with today's equipment running high speed internet instead of stepping backwards to the speed of older model PowerMac machines.
We're working with a few folks to see if this can be addressed at all with a driver update or if it's just all that the card can do. If this is all the speed we get, this machine is going back and we'll move on with another machine. My original plan was to install up to 4 of these 27" iMacs in our new facility, but that may have to change now if Apple is going to stay with these crippled controllers instead of giving us the speed we're paying for.
I'll update you guys as more information becomes available. To say I'm disappointed right now is an understatement. Wonder what I need to do to get on a beta test team because I seem to the person pushing all the systems further than any of their beta testers are. Everyone always tells me "you're the first person to find this......"
UPDATE #1 - 2/25/2010
I've been told the problem is limited to the 27" i5 and i7 Quad Core iMacs.
The Core Duo machines appear to support full Jumbo Frames across Ethernet. We're going to do definitive testing on both my i7 and a Core Duo machine this afternoon. Will update with more later.
UPDATE #2 - 2/25/2010
We took the iMac to one of the local Apple Stores where the technician at the Genius Bar confirmed that the Broadcom 5764 Ethernet Controller in the i7 iMac 27" does not support speeds over 1500. This same controller is in the i5 iMac 27" machine too.
From what he could gather, the Broadcom website is very vague as to whether the controller itself cannot support higher speeds or if it's just a driver issue. I've been told by outside sources that the documentation on the 5764 states it does not support Jumbo Frames so that leads me to believe 1500 is the max.
Now the Intel Core Duo 2 machines, which is pretty much the rest of Apple's lineup, all support Jumbo Frames. This includes the Core Duo 2 iMac 27" machines. I've returned the i7 and have ordered the 3.33Ghz 27" iMac.
I'm dumbfounded as to what happened with the design of the i7 and i5 machines. How was something as simple as an ethernet controller allowed to become a bottleneck on the flagship machine of a company? I don't know, but be aware that if you plan to use this in a professional environment and will require true high speed ethernet data transfer, as of right now, the i5 and i7 iMacs will not support that.
Again, to say I'm disappointed with Apple right now is an understatement.