MTU 1530 crashes finder

Question

MTU > 1530 crashes finder. Pretty much says it. MTU of 1531 will crash AFP connection attemps and kill the finder.
NICs support jumbo frames. Trying to share between two PowerMac G4's. Only MTU that works is 1530 and less. 1531 and over will crash the computer.
Need to get jumbo frames running.
When I go to try to resurect the finder I get a -600 error.

Answer 1

^ I don't really understand what that means?
Reader Reports (most recent first)
Apple PCI-X Gigabit cards: (follow-up from reader that reported on hawking cards on 8/29)
(added 9/1/2006)
"Hello again... Recently I found that the Hawking cards worked and are available via newegg, and I mentioned trying out the Apple "PCI-X Gigabit Ethernet Card" in two old PowerMac G4s to try to boost the file transfer performance (MB/S) using 9000 MTU on the Apple cards vs 1500 MTU on the hawking ones. The cards came, have nice LEDs (emerald green and sapphire blue), and are very easy to install compared to other cards. I'm testing using two powermac g4s (sawtooth's) one with the stock 400 MHz proc, other with a 1.8 GHz giga upgrade, both with 512 MB PC-100 ram, the test volumes are both raid-0 on both machines over two hdd. The Apple NICs are 64-bit.
The Apple "PCI-X Gigabit Ethernet Card" is based on the BROADCOM BCM5703CKHB chipset. The cards show they are able to handle jumbo frames in the ethernet tab in the network pref. pane. I set both cards to 9000 MTU which is usually greyed out if you have a non-jumbo card. Cards are connected over a DGS-1024D switch with 9.6k frames.
I tried opening a AFP to my PVR machine (the other PM G4), the window popped up to enter the IP (I entered the IP), then I authenticated (that worked fine), then the next screen after that is the one where you choose your volume. I chose the volume and pressed OK and the AFP froze.
I found that using a MTU > 1530 crashes the finder, forcing a hard restart. I tested MTU at 1531-1540 and at every step the finder is "(not responding)" after volume selection over AFP. Very odd. I called Apple enterprise support and they said the card has no free support (even though I just bought two of them less than 2 days ago) and it would cost $199 to get started on a support case to work on an explanation why 9000 MTU causes the crashes. I returned the cards.
But before I return the cards I'll mention the performance at 1530 MTU. The xfers from one G4-A raid-0 volume to G4-B raid-0 volume produce a STR of about 25 MB/S. The Apple NICs perform very slightly better than the hawking units. The STR somestimes hit 26-28 MB/S. I used a stopwatch and the file size to get the MB/S.
The performance is exactly the same as the Hawking cards, but at 4 times the price. Not a very good bargain huh? The Apple web site says that the PCI-X Gigabit Ethernet Card requires a 800 MHz G4. Funny, as the card works semi-fine in a 400 MHz G4, albeit only at 1530 MTU. Perhaps a 800 MHz G4 is needed for 9000 MTU? Apple had no ready explanation why this is so, and mentioned it would cost $200 to start a ticket. That's how much both cards cost.
I contacted Corky at Small-Tree and he said the 90mt is my best bet for using jumbo frames and copper gig-e on a powermac g4. The 90mt is $150 a pop. He said that no one has ever tried one in a sawtooth as far as he could remember. Once my apple RMA posts to my paypal I'll drop $300 for 2 90mt's and try it out. If they can do 9000 MTU as he claims over AFP I'll keep em only if they get me over 25 MB/S.
-Doug "
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