Slow copy speeds to USB in Lion

I have done 2 clean installs to date and can confirm it does not fix the issue. Transferring files to USB flash drives is painfully slow, and the progress is jittery.

I'm also not sure that it's only affecting a small percentage of Lion systems since all the Lion systems I have access to through family and friends are affected, I think it's probably just easy to miss the problem for most people (none of the family or friends had a clue it was happening).

I have also tried going back to Snow Leopard between clean installs to double check SL is problem free, and it was.

Have you tried booting into 64-bit mode by starting up your Mac while holding down the "6" and "4" keys?

Also what kind of Mac do all you guys use? I have Mac Pro (2009) also.

Have you all checked for any available firmware updates for your Mac at support.apple.com? I think Software Update is supposed to do this automatically, but I could be wrong. I seem to remember having to manually update a few firmware updates over the years.

I would also try a PMU reset, on the off chance something in the USB power level or regulation is out of whack. Card readers draw not insignificant current from the USB bus. Maybe if it's not getting enough juice, or it's noisy, the card reader's microcontroller drops its output speed so as not to risk data errors or damage to the flash memory itself? Grasping at straws here but it couldn't hurt to reset the PMU and find out.

To see how to reset yr PMU, google "reset PMU Mac Pro" (or w/e your Mac model is).

Hope this helps!!

I was just able to correct this problem.

Step 1.

Shut down your computer.

Step 2.

With powe off, SIMULTANEOUSLY press shift-control-option-power and hold for 5 seconds. Release SIMULTANEOUSLY. The computer should not power on.

Step 3.

Reset PRAM. Hold P-R-Command-Option as you startup until you hear the startup sound a second time. Release.

My speeds returned to normal. Before this, 7GB transfer on USB took a little over 2 hours. Now, it took about 9 minutes. Perfect.

Cool, guess I may be right about the PMU. People should note: the above post step 2 only works in certain Macs. Make sure to Google up what is the correct procedure to reset the PMU on your specific Mac and do that for step 2 in the previous post.

I'm still getting poor speeds after resetting the PMU and PRAM, about 11 min for 1.81 GB (so less than 3 MB/s). I hope it works for others but no luck for me.

Thanks Sean.

I would also like to say thanks to everyone for contributing so constructively to this discussion.

Unfortunately, following your steps of resetting the PMU (SMC in Intel Macs - see Apple's guidelines for doing this) and resetting the PRAM did not correct the problem for me either.

I've also used Onyx to clean and clear every conceivable nook and cranny of my iMac to no avail.

Interestingly, my USB data sticks now appear on the desktop much quicker after the resets, BUT, the 'jerkiness' and first reported amount copied are a little worse if anything than before.

Cheers

Mitch

thanks for the tip, if nothing else i'm amazed at the myriad Mac startup options.

unfortunately my month old Macbook Air still takes 30minutes to transfer a 730Mb file between usb sticks. copying the same size file on my 32bit Ubuntu 9.04 shuttle box between the same memory sticks takes less than 3minutes.

this thread if nothing else has at least lead me to a faster way to copy my memory sticks, use linux! 🙂

cheers

bruce

Just installed OSX 10.7.3 hoping it would resolve the slow USB copy speed problem and it's actually made USB copy speeds worse - a 550Mb file used to take about 5 mins to copy, now it's consistently at 6 minutes and the copy process takes considerably longer to begin as well.

* sigh *

Hi Guys,

I just upgrade my 13" mbp to Lion and noticed slow down in USB speed as well. Tried the PRAM and PMU resets, turning off bluetooth and nothing worked. I did try a clean install of 10.7.0 and my USB speeds returned to normal. When I migrated user settings, USB went to crap again.

Now, I regularly use USB for transferring for photos and to usb flash drives. I also have an external western digital for backups. My initial upgrade to Lion went fine and USB speeds were normal. I'm pretty sure something happened with the 10.7.1 update that borked the USB transfer speed.

I'm going to backup and try a clean install from DVD and NOT migrate user settings (PITA) and see if that works again. Either way I'm having Windows flashbacks - argh!

Same here, just noticed that in 10.7.3, it takes over 10 minutes to copy 1gb thru finder. But other types of copies are not affected, like chronosync or CCC. Not sure if it was the last OS update however, as I have not tried copy to USB flash drives for many months now. But now I need it. Arg...

Same here. Configuration: Macbookpro 2011 2.3 Ghz Intel core i5, OSX Lion 10.7.3.

Using a bluetooth Apple Magic mouse, no other peripherals.

I copied 1,852,784,640 Bytes via standard USB port to a 2 GB FAT32 formatted USB key.

This took me 21min15 sec. (1.386 MB/sec or 11.625 Mbit/sec!)

Copied the same files to a simple EeePc Netbook with Windows 7 & Atom processor.

It took 3min10sec. 6.7x faster (9.3 MB/sec or 78.01 Mbit/sec)

Both are way below the 60 MB/sec or 480 Mbit/sec maximum USB 2.0 speed. But the USB speed of the MacBook Pro is simply un-workable. Crap.

- Apple, it just works. Except when it doesn't.

Here is how I noticed significant speed improvement

When I copied a folder with DMg and other compressed files it took forever.

Copying these files individually, aka not oving the entire folder, the speed was up to what it sould be.

Ilife dmg as a dmg file transferred in 2 minutes, ilife folder with dmg file inside the folder was estimated to be 3 hours.

I hope this helps.

>I hope this helps.

No, unfortunately it doesn't.

For the tests I did I used just one folder containing JPG's, copying this from HDD to USB-key.

I did the tests a second time after I reset the PRAM, reset the SMC, rebooted and turned off all non-relevant memory resident software. Exactly the same result (even a little bit slower).

This is a structural OSX Lion bug.

I gave up hope waiting for a solution. Because I think Apple is more interested in trying to sell me the next IOS device than fixing their buggy software for which they've already received my cash.