No jumbo frames (MTU 9000) with new Core i5 iMac?

Yes, it's brand new, bought it two days ago... Apple Care support guy's suggestions to get MTU working with jumbo frames were all fruitless, I agree that it's in the kernel support.

I'm going to take it to the Genius Bar as planned and insist on at least a swap/replacement with a brand new i5.

What usually happens in those situations is that a swap is a hard sell if the problems you're having aren't repeatable by the genius in the allotted 15 minutes. I'm fairly certain I can get the AHT issue to happen on demand since it was consistent for me yesterday 3 times in a row. And so far the iMac wired ethernet has failed to work when coming out of sleep twice now, hopefully that's consistent as well.

The Apple Care guy said that they would run other diagnostic tests (not AHT disc) to see if there's some sort of hardware problem. One possibility is that my AHT disc is bad, I suppose... Even if the other diagnostics tests com up clean, with what I've seen so far I'd still be inclined to insist on a replacement since this thing is really hinky.

Then again, would a replacement be any better? If the MTU issue requires a kernel or driver update, any replacement will have the same MTU issue, but then again maybe the replacement won't have the AHT issue and the ethernet-no-worky-after-resume-from-sleep issue...

I'll post what happens tomorrow after my appt with the genius...

Interesting -- so my 'wake from sleep' issue may be one of the Mac being dropped from the network when connected via the wired ethernet port. Interesting way to look at it.

Presumably when this happens I can check the network properties and see whether I have an IP address assigned via DHCP (or not)?

I guess it's one thing if I see something unexpected and not the 192.168.1.1xx which should be there (was there previously), but another if I still can't get on the network if it shows a 192.168.1.1xx value.

The next time it happens I'll check; however my Genius Bar appt. is in about 4 hours and I'm at work so I may not get a chance to experience it before then.

If all goes as I hope, worst case I'll come home with a replacement (new) i5, othewise what I'm actually hoping for is to return it and wait it out until the i5's get through their 1.0 revision growing pains...

Well, unfortunately it's as I feared it would go... I had exactly 15 minutes with the Genius Bar, the guy before me ran late, my session was rushed, he couldn't duplicate a couple of the issues I mentioned to him, didn't even get to try the AHT issue I experienced, was not able to duplicate my ethernet connectivity issue in the couple of forced sleeps he initiated, all in all from his perspective my iMac i5 was 100% functional and perfect.

His first suggestion was to let them troubleshoot it for a couple of days, which is not acceptable to me since I've owned it for exactly 4 days and would be without it. Spend $2K, have problems for 4 days, then have to go through a repair process? No thanks...

He offered to send me home with a replacement which I considered but given the other issue I'm having with it (the whiney LCD monitor if I set brightness down below 80%) without having the ability to verify the replacement wouldn't be whiney then there was no point in bringing another one home.

As much as I love this computer, I really feel that my problems are indicative of a 1.0 release.

I managed to get him to refund 100% of the purchase price, which I feel was appropriate. He was iffy about it given that he was unable to validate a single thing I said. He couldn't hear the noise (I just barely could -- it was noisy but I was sitting right next to it...) and I said I wouldn't bring it back into my house with that noise.

I'm sending this from the store floor, 100% refund in hand. I'm quite disappointed with the machine but at least Apple did the right thing and gave me the refund.

I'll wait a few months to let these kinks be worked out of the product before I dip my foot back in the Apple Quad Core iMac pool...

Incidentally, as I type this from the Apple Store floor, I just checked the network properties for the Ethernet adapter -- I find that Jumbo (9000) IS a valid selection on Ethernet!

This is on a 27" Core2Duo iMac, which is all they have on the floor at this time. And there are only 2 of them. The other 2 new iMacs are the 21.5's.

So whatever they did with the Core i5's have definitely made it unavailable, whether by accident or by design.

Be warned.

Does this mean that all i5's cannot do jumbo frames? I can't make a blanket statement like that, but so far nobody has indicated that they CAN enable Jumbo Frames on an i5. I also have not read anywhere that it's available on the i7's either.

But I do confirm that it IS there for the C2D 21.5" and the C2D 27".

Seems that all that is needed is proper kernel support for the Broadcom ethernet chip in the i5/i7 and it will be possible, but that depends entirely on Apple pushing us a driver update.

I've got an i7 on order (since I returned the heinously disappointing and buggy i5) and hopefully when it arrives the Jumbo frame fix will arrive shortly thereafter, but I fully expect that the i7 will not support jumbo frames out of the box.

Then again, I suppose I'm also expecting to have some other show-stopping hardware problem, like LCD panel whine at reduced brightness, tearing, yellowing/non-uniform color temp, display black-out or flickering, horribly loud hard drive noise, excessive heat, or any one of the multitude of other complaints here. =)

@healeydave -- A reboot got my wired ethernet working again. And the 'disabled when wake from sleep' issue was intermittent, sometimes it would work fine from sleep. Sorry you're having such a bad time of it, I'd say it needs to go back to Santa's workshop and you need to get your money back. All of it.