There are typically a number of steps involved in getting data from one place to the other. Whether burning a CD, downloading a memory card, or copying files from one hard drive to another, it’s never quite as simple as “my drive is fast, so the copy will be fast.”
This could become an extraordinarily long and technical discussion. I’m going to do my best to communicate the concept simply through metaphor and examples. The super-geek stuff will come below the jump, so you’re welcome to ignore it if you like.
Why a “Chain”?
A chain is a simple way to illustrate the concept. Imagine if you will, a short length of chain rated to hold 20 tons. Each link in the chain must individually be rated to 20 tons. If we change just a single link to one with a 5 ton rating, then the entire chain is downgraded to 5 tons. Likewise if we upgrade just one link in the 20 ton chain to 100 tons, overall the chain is still only capable of 20. Upgrading a single link does not upgrade the entire chain. Downgrading a single link downgrades the entire chain. The same is true for the data pathway from point A to point B.
The Data Chain
Consider this (simplified) list of steps an image file takes when going from your CF card to your hard drive. Every step represents a link in the chain, and impacts the time it takes the file to copy.
The CF card itself → USB cable → USB hub → USB cable → USB port on the computer → (ABSTRACT*) → HDD (hard disk drive) interface → HDD cable →HDD.
Lots of steps, yes? Just like in the example of the 20 ton chain with a single 5 ton link, the slowest single step in the chain determines how long the file takes to copy.
Vivian has a computer that’s a few years old. It has USB2 ports, an internal HDD that was top-of-the-line at the time of purchase, and she recently bought some new high-performance 600x CF cards for her cameras. Vivian’s good friend tells her about some fancy new USB3** card readers, and how amazingly fast they are. Viv loves the idea of getting her cards downloaded faster, so she buys herself a couple. Has she improved her situation? Unfortunately no. Vivian’s fancy new card readers will work in that they will dutifully transfer data***, but the download time will remain exactly the same as it was on her USB2 card readers. She needs USB3 along every USB step. Laptops typically have limited upgrade-ability. Viv may not have many options in this case short of buying a new laptop with USB3, though some laptops support minor upgrades through express ports. If you’re unsure, contact your neighborhood nerd for help.
Sebastian has a desktop computer that he bought last year. It’s pretty fast and he’s happy with it, but it didn’t come with USB3 support. He’s got fast memory cards, a USB3 card reader, and his internal hard drives are all lightning quick. Sebastian wants to be able to download multiple CF cards at once, and have the downloads run as fast as the card is capable. All he needs to do is buy a USB3 interface card, pop the lid off his case, and install it. This isn’t nearly so hard as it sounds, but if you’re unsure consult your neighborhood nerd.
Josephine just unboxed her new pride-and-joy: a 32 core super-computer with 128GB of RAM, four SSDs in striped RAID, and three 30″ displays for an obscene amount of desktop space. Naturally she has USB3 ports, cables, and card readers to match. Josephine made this purchase because she upgraded to a new 64 megapixel camera, and she expects the files to be large. Josephine shoots digital, but she’s very thoughtful and only presses the shutter button when she knows it’s going to be an amazing photo. Because of this, Josephine has never felt the need to upgrade her aging CF cards, which frankly, are pretty slow. Josephine’s computer will process those files crazy-fast once they’re inside the computer, but because the CF cards are old and slow it’s unlikely her download times are going to improve over her previous system.
If I’ve written this well, then by now you get the point. The top speed is only as fast as the slowest step along the way. Don’t make the mistake of running out and buying USB3 card readers if you only have USB2 in your computer and cannot upgrade.
This article is likely to live on the internet for quite a long time. Today, in 2012, USB3 and Thunderbolt are both considered very fast. If you’re reading this in 2016 they’re likely average. If you’re reading this in 2020, they’re probably pretty slow. Certainly you’re on USB4, or Thunderbolt2, or something altogether newer. There was a time when USB2 was amazing. While the specific names and specs will change, the concepts remain sound.
*There are many steps inside the core of the computer that most users have no control over, and can only be upgraded through the purchase of a new machine. I’ll gloss over them in the interest of simplicity.
**USB3, USB3.0, Super Speed USB – these are all the same spec / version of USB.
***The beauty of the USB spec is that new devices are always backward compatible with older devices. A USB3 card reader will transfer data when plugged in to a USB2 port, but it will slow down to USB2. A USB2 card reader will work on a USB1 port, but it will slow down to USB1 speeds.
If you’re hungering for more examples and more complicated setups, roll up your sleeves and hit the “continue reading” button below the sharing icons.
UPDATE: 5/3/2013 if you’re using mRAW or sRAW in your workflow, check out my recent article to see if you’re actually saving yourself hard drive space.
UPDATED 4/3/2012 to add metric for mRAW to CF, sRAW to SD.
I am in love with my new Canon 5d3. A huge sigh of relief for me is the dual card slots, so I can always have a backup. Unfortunately there’s a big performance difference between the SD card slot and the CF card slot.
If Canon had chosen to support the UHS-1 standard, we’d get roughly equal performance. As it is, they supported SDXC, but not UHS-1. (For the record, the camera will work with a UHS-1 card, it just won’t support the improved write speeds. I’m using one in my camera and it works fine.) Continue reading Canon 5d mark III | Record Separately Vs. Record to Multiple | Performance Comparison
The Canon 5d mark III officially went on sale yesterday, and many of you already have one in your hot little hands. (Mine comes on Monday!!)
If you eagerly ran out and shot a few frames, then tried to import into Lightroom, you discovered that Lightroom isn’t ready for the 5d3 yet. Full-release support is likely coming soon, but in the mean time there’s a way around this issue. Download the DNG Converter 6.7 Release Candidate from the Adobe Labs site. Continue reading Adobe Lightroom and Canon 5d mark III
You buy computer stuff. Even if you hate it, it’s a part of your job. Every manufacturer wants you to think their product is the best, so they’re constantly showing you the biggest number they can. Bigger is better, right? Sometimes. (My girlfriend assures me it doesn’t matter.)
For the moment, consider these speed ratings:
- 9600 b/s
Which is the fastest? The first thing to recognize is that the size of the “b” matters – a lot. Like, to a factor of eight. Each prefix multiplier is 1,000x it’s previous. Continue reading Case Sensetivity in Speed Ratings? Yup, They Matter
SD cards and CF cards. They all have performance limits. Thankfully there seems to be a trend toward actual MBps (megabyte per second) ratings, but a lot of older and some newer memory cards use the X (ex or by) rating to indicate speed.
But 266x What?
266 * 150KBps = 39900KBps / 10 = 39.9MBps (rounded to 40 by most manufacturers) means you have a 40 megabyte per second memory card.
WTF? Why 150KBps??
CDs were born for music. Your music CD player reads data off the disc at the rate of 150KBps (at least, it did before you put it out in the garage to gather dust.) The very first CD drives in computers also read discs at this same rate. When advancements started producing higher performance, that performance was indicated by manufacturers as some multiple of the base speed of 150KBps. A 2x CD drive (yeah, I actually had one) was a blazing-fast 300KBps device. The ex or by moniker was born. A 40x CD drive therefore had a peak speed of 6000KBps, or 6MBps. (Don’t laugh – we thought they were awesome.)
Most memory cards indicate the speed at which they can read data. With few exceptions, cards can be read-from faster than they can be written-to. The read speed and write speed are asynchronous (not the same.) Sometimes this difference is significant, so do your homework if the write performance is important.
133x = 20MB/s
400x = 60MB/s
600x = 90MB/s
A great deal of thanks goes to the folks and participants at the Notebook Review Forums. In particular, the HP Envy 15 (3XXX series) Owners’ Lounge thread. This article is primarily a distillation of the 158+ pages written there about this and other issues, both good and bad.
There aren’t a lot of laptops with IPS screens in them, so when one comes along it’s pretty exciting. Unfortunately the IPS panel in HP’s Envy 15 will leave more red in your face than it can display. (You must get the “radiance” display upgrade to get the IPS screen.)
If IPS is a new term for you, it stands for In Plane Switching. Not all flat-panel LCD screens are created equal. There’s a wide variety of underlying technologies, all designed to solve a problem, and often that “problem” is cost.
IPS is the kind of LCD that gives you very wide viewing angles without color shifting. It’s also associated with the best color quality and widest color gamuts. It’s also expensive. For some reason, laptop manufacturers don’t think we’re willing to pay for good screens.
Sadly on the HP Envy 15, in spite of having an IPS screen, it has an embarrassingly small color gamut. Continue reading The Problem with Red on HP’s Envy 15
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Adobe Photoshop Lightroom 4 does so many things right. The IQ improvements in the develop module are significant enough that at times I feel like I’m shooting on a whole new sensor.
The book module is also a welcome addition, and one that I was looking forward to tinkering with. I have high hopes that it can replace InDesign for most layout jobs. That said, currently the only way to get custom layouts out of it is via PDF. I work with a well regarded bookbinder in Texas who only accepts spreads as JPEGs, so this makes the entire book module a non-starter for me. Continue reading JPEG output in Adobe Lightroom 4 Book Module
Adobe Photoshop LightRoom 4 has dropped, and I must say it came faster than I expected. This is good news of course, along with the 50% price cut.
Anyhow, there’s plenty of coverage of the software ALL OVER the ‘net, so you don’t need me to tell you about it yet again. What I am going to do is target very specific things that I find useful.
Today’s tidbit is about the new DNG format. Adobe LightRoom 4 introduces the DNG 6.6 spec. DNG 6.7 is coming very soon, and adds support for the Canon 5d mark III and a handful of other brand-new cameras. If you need 5d mark III support today, you can download the “release candidate” or “RC” version of DNG 6.7 from Adobe’s website. (A “release candidate” has passed beta, and is the version the software engineers believe will become final.) Continue reading LightRoom 4’s New DNG Spec Allows Lossy Compression