Why is my card-to-computer transfer so slow?

[robertbanks]

<p>I've been testing some of my cards with various readers and have been quite disappointed with the results.</p>

<p>The cards are both Lexar: XQD 1100x 64Gb and CF 1000x 64Gb.</p>

<p>For transfer from the XQD I used a Lexar USB 3.0 reader and a Sony ExpressCard reader.<br>

For transfer from the CF I used a Lexar USB 3.0 Dual Slot reader and a Lexar Professional ExpressCard reader (updated a driver so it could read UDMA 7).</p>

<p>I tested the USB readers' speed on 3 different laptops (two running windows 7 and one running windows 8). Only one of these laptops has an ExpressCard slot for testing the other readers.</p>

<p>In all cases the transfer speed I found from the card is around 40-50MB/s.</p>

<p>I've seen reviews where a Lexar 32Gb 1000x CF card with the dual slot reader achieved over 90MB/s (e.g. Rob Galbraith).</p>

<p>Any ideas why I am not getting speeds close to this?</p>

[dcstep]

<p>So, it didn't matter which reader that you used?</p>

<p>I'm using the Lexar 32G 1000x CF card with a Lexar USB 3.0 reader and getting very fast downloads, but I haven't bothered to measure.</p>

[pcassity]

<p>Are you using a 3.0 card reader with an extension cable to your laptop? I was having the same problem. I had to get rid of the extension cable. Slowed the transfer speed significantly. Also purchased a new 3.0 reader. Bought a Hoodman. Very happy with the transfer speed now. Still not close to what tey say 3.0 will do, though.</p>

[rodeo_joe1]

<p>What are you writing the image files to? USB is a shared bus technology, and if you're transferring to an external hard drive also using the USB bus, then that'll practically halve the transfer rate.</p>

[georges_pelpel]

<p>Your Lexar USB 3 reader should be fine, I get fast transfers from mine.<br>

You have to make sure your computer USB ports are USB 3 though. If you computer only supports USB 2 it won't be able to take advantage of the USB 3 speed.</p>

[sem_svizec]

<p>How fast is your hard disk? Check with HD Tune. </p>

[Wouter Willemse]

<blockquote>

<p>USB is a shared bus technology</p>

</blockquote>

<p>My guess is this one, too... When testing these speeds, be sure that no other USB devices are active.<br>

Plus, laptop hard drives are seldom very fast, 50MB/s writing speed is not unexpected. Again, also make sure that there is no activity in the background using the hard disk intensively.<br>

But before jumping through all kind of hoops, I would first wonder how important it really is to get this 90MB/s... 50MB/s really is not THAT slow.</p>

<blockquote>

<p>Still not close to what tey say 3.0 will do, though</p>

</blockquote>

<p>It simply won't reach that as the bottleneck is the card itself. As the saying goes, the chain is as strong as its weakest link. Going from USB 2 to USB 3 removes a bottleneck, but that only means there will be another bottleneck somewhere else. There always is one....</p>

[bgelfand]

<p>There are several places for your bottleneck. I assume you are running an Intel powered laptop and I assume the card readers themselves are functioning properly.</p>

<p>1) Intel does not provide native USB 3 support on its 5-series, 6-series, or 7-series chipsets (the 8-series chip set that will be released with Haswell will have native USB 3 support). The USB 3 support you have is provided by another chip selected by the computer manufacturer and usually wired into one or more of the PCIe 1x lanes on the Intel chipset. The speed of USB 3 ports vary depending upon the USB 3 chip selected and the implementation. Speed is also dependent upon the chip driver. <strong>Are you running the latest drivers for the USB 3 chip on your laptop?</strong> Check the laptop manufacturer's web site for the latest drivers.</p>

<p>2) Laptops usually have but one hard disk, and laptop disks are not the fastest, unless you have a Solid State Drive. One drive means the disk can be very busy with system tasks like paging and with background tasks like your anti-virus program. A slow single disk can slow transfers considerably. Also when was the last time you defragmented you disk?</p>

<p>3) Your anti-virus program will scan the files that you transfer. This can slow transfer considerably. Most anti-virus programs load the virus definitions at startup and then page them out and page them back in as needed. This paging can cause disk contention with the copy not to mention holding up the transfer as the definitions are paged in. You can try disconnecting from the internet and disabling your anti-virus<strong> just for the test </strong>to see if this is causing a bottleneck. Most anti-virus programs are still 32-bit programs even though they can scan memory in a 64-bit address space. This means they will use memory only below the 4 GB line and will page.</p>

 

[Wouter Willemse]

<p>Brooks, nitpicking (because otherwise fully agree with what you wrote), but there is USB3 on ALL intel 7-series chips already. See for example here: http://ark.intel.com/products/64339/Intel-BD82HM77-PCH</p>

[robertbanks]

<p>Thanks for all your replies.</p>

<p>To clarify I was copying from the memory cards via the various readers to the laptop's internal hard drive.</p>

<p>As some noted, it did not seem to matter which reader was used (USB 3.0 or ExpressCard via PCI).</p>

<p>So I've just run HDTune on my "main" laptop (which I understand has an Intel 5 series/3400 USB controller chip for USB 2.0, and also a Renesas USB 3.0 controller and Root Hub, and which apparently has the latest drivers installed, disk was defragmented last week and is showing now as 1% fragmented, and I was definitely using the USB 3.0 connections ;).<br>

<br />Results were a minimum transfer speed of 40MB/s and a maximum of 80MB/s, average 69MB/s - so this ties in with my results and looks like the weak link in the chain.<br>

<br />Thanks again for everyone's input.<br>

Rob</p>

[blumesan]

<blockquote>

<p>but there is USB3 on ALL intel 7-series chips already.</p>

</blockquote>

<p>Curios to learn more. I am running an Intel Core i7 CPU. There is no port on the MB that will accept USB 3.0 input. I had to install a PCI card and appropriate drivers to achieve that capability. What did I miss?<br>

Thanks.</p>

[bgelfand]

<p>Hi Wouter,</p>

<p>Thanks for catching my error. You are absolutely right, the 7-series chip set does support USB 3.</p>

[bgelfand]

<p>Hi Mike,</p>

<p>The 7 in i7 refers to the CPU, not the chip set. I run an i7-980 (an "old" Lynfield CPU) on a motherboard that uses the P55 (5-series) chip set. Like you, I needed to install a PCIe card to get USB 3 support, since the 5-series chip set has no native USB 3 support.</p>

<p>Here is a link to the block diagram for the Intel P67 chip set (6-series, no USB 3 support):<br>

<a href="http://www.intel.com/content/www/us/en/chipsets/mainstream-chipsets/p67-express-chipset.html">http://www.intel.com/content/www/us/en/chipsets/mainstream-chipsets/p67-express-chipset.html</a></p>

<p>And here is a link to the the same diagram for the 7-series (USB 3 support):<br>

<a href="http://www.intel.com/content/www/us/en/chipsets/mainstream-chipsets/chipset-h77.html">http://www.intel.com/content/www/us/en/chipsets/mainstream-chipsets/chipset-h77.html</a></p>

 

[bgelfand]

<p>Hi Robert,</p>

<p>I suspect the choke point is your laptop disk.</p>

[francisco_salaquanda]

<p>Leave the cards in the camera, use Nikon Transfer to bring the files into ViewNX2 (it does error checking), save the NEFs as tifs and then open them in Lightroom etc. Each day I do a backup to an external drive and also a copy to iCloud for redundancy. Works for me.</p>

[chris_letts]

<p>If you check the posting I made about data transfer speeds you'll see that I 'only' got 50 MBps maximum even when using USB3.<br>

USB3 just isn't as fast in practice as in theory.</p>