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

Just to reiterate what Apple told me. It's not possible because jumbo frames are not supported at the physical level of the Broadcom chipset.

Let me come back to the performance testing with jPerf 2.0.2. Settings are TCP, 2MB buffer length.

It seems that the MBP does manage good results, even though without the jumbo frames support in Snow Leopard. However, the server (and other PC client) do have jumbo frames enabled, send/receive buffers set on 512, frames of 9014 bytes, 1GB full-dupex.

I guess it seems to even outperform my PC (Windows 7, C2D E6600, 4GB)... Real life tests seems to be alright as well, have transfered large ISO files over SMB without any problems (but no transfer rates available of course...).

These are the results with the MBP:
------------------------------------------------------------
Client connecting to 10.0.0.2, TCP port 5001
TCP window size: 0.13 MByte (default)
------------------------------------------------------------
[ 3] local 10.0.0.8 port 58781 connected with 10.0.0.2 port 5001
[ 3] 0.0- 5.0 sec 440 MBytes 738 Mbits/sec
[ 3] 5.0-10.0 sec 454 MBytes 762 Mbits/sec
[ 3] 10.0-15.0 sec 452 MBytes 758 Mbits/sec
[ 3] 15.0-20.0 sec 446 MBytes 748 Mbits/sec
[ 3] 20.0-25.0 sec 454 MBytes 762 Mbits/sec
[ 3] 25.0-30.0 sec 448 MBytes 752 Mbits/sec
[ 3] 0.0-30.0 sec 2696 MBytes 754 Mbits/sec
Done.


These are the results of my usual PC:
------------------------------------------------------------
Client connecting to 10.0.0.2, TCP port 5001
TCP window size: 0.01 MByte (default)
------------------------------------------------------------
[216] local 10.0.0.3 port 52681 connected with 10.0.0.2 port 5001
[ ID] Interval Transfer Bandwidth
[216] 0.0- 5.0 sec 390 MBytes 654 Mbits/sec
[216] 5.0-10.0 sec 412 MBytes 691 Mbits/sec
[216] 10.0-15.0 sec 410 MBytes 688 Mbits/sec
[216] 15.0-20.0 sec 416 MBytes 698 Mbits/sec
[216] 20.0-25.0 sec 414 MBytes 695 Mbits/sec
[216] 25.0-30.0 sec 422 MBytes 708 Mbits/sec
[216] 0.0-30.0 sec 2466 MBytes 689 Mbits/sec
Done.

Message was edited by: InsjaHH

Do you have any iozone data to report too? Jperf is good to have, but if you're mostly planning to use that for file transfer, I think iozone is better.

I'm testing my old MBP early 2008 versus my new MBP mid 2010, and I see a significant performance decrease. Actual results against a ReadyNAS Duo XRAID fileserver using AFP:

WRITE SPEED
Macbook Pro 2008: 25.0 MBytes/sec
Macbook Pro 2010: 19.6 MBytes/sec

READ SPEED
Macbook Pro 2008: 23.7 MBytes/sec
Macbook Pro 2010: 19.7 Mbytes/sec

Granted, the ReadyNAS couldn't entirely fill the gigabit pipe to begin with, but I'm still seeing a 20% throughput decrease.

At least my Drobo FS is still faster, good to see that it's not as slow as I suspected it was compared to other NAS devices.

I have a 17" i7 MacBookPro (Mid 2010 Unibody) which uses a Broadcom 5764 gigabit chip for its cabled ethernet interface. There appears to be no Jumbo frame support in this kernel extension/driver - kext (1500 MTU max). I have a 15" Macbook Pro (non-unibody) and a Mac Mini both use a Marvell Yukon 88E8055 gigabyte chip for their cabled ethernet interface and they have Jumbo Frame support (9000 MTU and down) as they should. Lack of Jumbo Frame support is causing my backups and other copies to run much longer then they did on my old 15" MacBook Pro. I have opened a case with Apple Care to get issues escalated to engineering since the chip is clearly capable of Jumbo Frame per Broadcom's site. All systems are running Mac OS X 10.6.4. If you have Apple Care and your Mac has a broadcom 5764 gigabit chip and no Jumbo Frame support I suggest you also open a case. It is the Sata driver issue for the unibody MBP only running 1.5 vs 3.0 again.

Are you saying they changed the chip again? :shock:
Well at least it can be changed via firmware then. The chips in the iMac do not have the ability at all, so this is a small step in the right direction. The new Mac Pro continues to have Jumbo Frame support so they are not gimping every single Mac at least!

OK, The latest info I have is that the current selling MacBookPro and iMacs use the same Broadcom 5764 chip which either the driver/kext does not implement Jumbo Frames (9000) for this chip or the chip does not support Jumbo Frames (9000) can't get a straight answer from Apple or Broadcom (waiting from a call back from Apple Care who escalated the question to engineering). The new Mac Mini uses a different Broadcom chip which DOES support Jumbo Frame (using same driver/kext). For MacBook Pro 17" users you can purchase an ExpressCard Adapter that supports Jumbo frames like the LinkSys EC1000 Gigbit ExpressCard Adapter which uses the same Marvell Yukon chip the previous MacBook Pro (non-Unibody) and MacMini used.

I don't know which network chip the pre-i5/i7 Unibody used for the ethernet connection.

So I found a work around for my problem with the LinkSys ExpressCard but I hope Apple just made a honest mistake like the SATA driver issue and not cutting cost because they think no one would notice and no ones use it sort like the Express Card slot on the 15" Unibody that was removed to add an SD slot instead of just putting an SD slot converter in the ExpressCard slot which would have been a more elegant solution becuase there are lots of use that do use the ExpressCard slot. So we will see.

"Face it, folks -- moving to this Broadcom chip in the iMac line, one that does not have jumbo frame support, was a conscious decision and I'm sure the decision makers were well aware of the missing jumbo frame support."

Which is why the new Mac Mini does support jumbo frames and the MacBookPro doesn't?

Message was edited by: wqerwqerwqerwqer

Hmmm they both have Broadcom chips just different ones.

OK, I just reverified this so I don't look like a fool, and the new MacMini does support jumbo frames as indicated in the Tech Specs for the Mac Mini, as does the Mac Pro. While I do not have any inside information I cannot believe this is a marketing / produce segmentation decision, if it were they wouldn't specify jumbo frame support on the Mac Mini.

I use my system all day, every day to make a living. I make frequent use of large VM images stored on a NAS (Synology) and I am planning an upgrade of my entire network to Gigabit Ethernet with jumbo frames support because I frequently move large files around (20GB+) So imagine my surprise when I want to upgrade from a 2 year old MacBook that does support JF to a iMac that doesn't, I'm going to be missing a required feature. The response to get a MacPro is not acceptable, because even though I use my system professionally, the Core i7 in the iMac is more than enough processing power. A comparable Mac Pro setup with a monitor would cost over $4,000, I do not need that kind of power nor do I want to use the electricity etc required, and my entire budget for the iMac and network upgrades is $5,000.

This kind of thing from Apple is very disappointing. I fail to understand how they can get so many things right and screw up a detail like this. Do the product managers at Apple think that no one with technical ability actually uses Macs? I'll be proceeding with my network upgrade but I'll not be purchasing a new system until they correct this issue (and hopefully don't introduce other issues when they fix this one).

No wonder my 27" i7 is so slow at accessing my readynas nv+. Time machine backups are noticeably slower than my previous core2duo 24".

I've turned off jumbo frames on everything in my home but haven't had the chance to verify if throughput went back to something reasonable.

Yes, I'm disappointed and surprised that network performance is slower on my new Mac. ***!?

I just purchased a 15" MBP (6,2) a couple of weeks ago and connected my Ready NAS NV+ RAID to it. I noticed that the last week and a half that performance copying files to it was quite slow - at least 10 times slower than my 3 year old 15" MBP (4,1).

When I went to the network settings, I couldn't set the MTU higher than 1500.

While I really appreciate the new faster CPU speed, reading and writing data to the RAID at 1/4 to 1/8 the speed of the 3 year old machine is not going to work.

Also without an express card slot on the new 15" - a 3rd party network card can't be used.

What are my options?

Does anyone know if Apple will let me upgrade this BTO laptop to the 17" version of this machine - I wanted to avoid the large size - but I need the performance.