Sony’s SxS advantages. Are they real?

sxshor.pngSony wants to promote the speed advantages ExpressCard Flash Media (ECFM for short) are reputed to have over PC cards. In Sony’s SxS brochure, bullet point numero uno is “Faster Transfer Speed.” The chart that accompanies this promotion states 800 Mpbs (sic) versus 640 Mbps for PCMCIA (PC) cards.This would mostly have to do with the ExpressCard standard being a serial solution as opposed to a parallel solution. Does this sound familiar?

The latest laptop and dsktop computers are primarily outfitted with SATA or Serial ATA hard drives. These replace older ATA or Parallel ATA drives that we “used” to use not so long ago. By all accounts, the SATA interface is smaller, cheaper and considerably faster than we were achieving with the third generation of ATA, even with those wide, ungainly 80-conductor cables.

But does Sony’s SxS, and by that account, ExpressCard live up to the hype? Sony makes it clear… nay, they hammer the point that the PC-Card standard has been closed and that the trade association (PCMCIA) urges all further development to be made on the ExpressCard technology. (Note: ExpressCard is a trademark of PCMCIA, but it’s easier not to have to code a “tm” after every single usage) I could similarly note that CD’s have been supplanted by DVD’s and those have been supplanted by HD DVD and BluRay, but every computer can still read CD, software is still distributed on CD, music is on CD, etc. “Old” standards, like Parallel ports on PC’s, are used long after they have been “closed.”

The preliminary specification sheet touts “Sony’s SxS PRO Memory Card. Because it uses a serial interface, it transfers at a faster bus speed, is more reliable and comes in a smaller size resulting in a significantly lower storage cost per minute of high definition video when compared to conventional PC parallel cards.” Wow. Quite a claim. It would be more effective if the various parts of the claim were actually related to each other. Let’s work backwards:

The size of the card has nothing to do with the cost per minute of storage. In fact, the size of the card is just some 40% smaller than a PC card, which was plenty small. Honestly, if my livelihood is riding on the footage I shoot, I’d rather have larger physical media that’s harder to lose, can’t fall out of my pocket unnoticed, etc.

More reliable” is missing the rest of the comparison… More reliable than what? Tape? Hard drives? SmartMedia? PC Cards? The black boxes used to store flight data recoverable after a crash? (actually- those use tape media. but I digress.)

Faster bus speed” is actually less useful to the camcorder because XDCAM records at 25 & 35 Mbps. Compare that to DVCPRO HD that records at 100 Mbps. Even Sony’s literature makes it clear that, on similar eight gigabyte flash media (7.4 gig usable) SxS can hold 30 minutes of 1080i60 footage versus DVCPRO HD storing only squeezing 8 minutes on a PC card. See for yourself:


But Sony plays a little loose with the specifics here because the camcorder records in both 1440 x 1080 i 60 (25 Mbps HDV) and 1920 x 1080 i 60 (35 Mbps XDCAM). In Sony’s own 8g card chart, they say it can record approximately 25 minutes of XDCAM, or 35 minutes of HDV. So if it is 25 or 35 minutes, how does the very next chart, on the same page, say 30 minutes on an 8g card? What 1080 format & data rate were they using? It doesn’t say.

Now. If XDCAM is such an efficient codec (and I have to admit, the test footage they showed was beautiful- as it should be), and it has such a low data rate, why on earth would they imply “serial interface, faster bus speed, more reliable, smaller size” has anything to do with “significantly lower storage cost per minute of high definition video”

Sony has announced flash media prices that are about the same as current P2 cards of the same size. If an 8gig card costs about $550 (that’s about $56 a gig) then anyone would like to put as much high-quality video on there as possible- both from a run-time standpoint, and for cost effectiveness. But Sony did not say: the XDCAM and HDV codecs have proven themselves for broadcast HDTV and now you can use these highly efficient codecs to achieve the lowest cost per minute on a broadcast flash media camcorder. They did not state the underlying truth, but rather pointed to a smaller physical size as a reasons for cost effectiveness? That makes no sense.

Let me throw Sony a bone here. I know I’m very critical. So let’s take one of those other aspects and make it work for them. Sony says SxS has a faster bus speed, and this is true. You’re not going to read or write to most any other flash media (except maybe a SATA flash drive) faster. Even Class 6 SDHC cards are 6 MBps. SxS touts upwards of 100MBps. Even though we know that nothing reaches its theoretical maximum, 100 is far greater than 6. Compact flash cards also tout high throughput. The SanDisk Extreme IV claims 40 MBps read and write. But 100 is far greater than 40.

But that speed is clearly not needed for video recording or playback.
800 Mbps is not needed when your VBR data rate peaks at 35 Mbps.
No. Where that speed comes into play is when you have two cards and are “live swapping” those cards in the camcorder while shooting. The longer record time gives you more time to dump the other card in a computer. The faster bus speed means you can dump all that data off the card faster than if it were a PC card, or any other current flash media for that matter.

This means you’ll need to have a laptop with a compliant ExpressCard slot, and the special little drivers that will recognize the media.

What? A driver? You thought everyone was playing by the ExpressCard specifications here and interoperability was assured? Ha. This is the new millennium. DCMA. Proprietary media. Sony’s press release states, “with the optimized technology protocol for controlling communication between hardware and the card, the SxS PRO card realizes its high-speed data transfer at 800 Mbps. What will be the speed of the media without the optimized driver? Good question.

How many laptops have two ExpressCard slots? None.
Why need two? Well, are you editing your HD video with Firewire 400 drives? Or are you using SATA drives? Probably SATA. And, how, then, are you connecting your SATA drives to your laptop? With the non-existent SATA port? Or with an ExpressCard that gives you SATA ports? Ahhh. With one ExpressCard slot, and two ExpressCard needs, you’re going to have to find a different way to connect the drives, or copy the media.

Lastly, what if you want to load media onto a desktop system?


Well, that was the teaser in my last post. Sony quietly provided a solution for that: the SBAC-US10 SxS USB Memory Card Reader /Writer. (Props to Panny for simple names, like: “P2 Store.”) I scroll my finger down the page, past power requirements (it needs a seperate 3w, 12v supply, it’s not USB only!), down to the data transfer speeds and my mind has to reel back from the uber-fast 800 Mbps to this USB 2.0 device’s touted 160 Mbps write, 240 Mbps read- asterisk. As in *.

Continue down to the bottom of the chart.
And find the same text that accompanies the 800 Mbps speed claim:
* The above data transfer speeds were measured by using a benchmark software. Actual data transfer speeds vary by the measurement conditions. Please refer to the ‘’ (available in November 2007) for information on measuring methods.

I just tried it. It’s “Not found” for now.

Let’s do some math. An 8 gig card holds 7.4 GB of media. That’s 7.4 x 8 = 59.2 Gb of data.
Then say the “EX-drive” (above) reliably transfers data at 200 Mbps.
59200 Mb of data ÷ 200 Mbps = 296 seconds ÷ 60 = 5 minutes.
Unless my math is wrong, that’s still pretty darn doable in a production situation.
(please, correct me if I’m wrong.)

So is SxS all its cracked up to be?pd50.jpg
THAT’s the question.
My opinion is that it’s a new way to do what we’re already doing with other media (for example, Professional Disk). EX offers a few slight advantages over PD, size being one of them. But when it comes to needing to archive the media from SxS sticks at the end of the day, you’re still going to have to put the media onto something. PD not only allows you to save the “camera originals” but you can also store the editing project files, associated artwork, Photoshop files, script and more- on the same PD as the original camera footage. Now Dual layer PD disks are available that hold 50 gigs of data. The 23 gig disks cost $20. That’s 87¢ a gig; a far cry from SxS’ $56 a gig. I can afford to archive camera originals at 87¢ a gig.

What makes more sense to you in the long run?

8 thoughts on “Sony’s SxS advantages. Are they real?

Add yours

  1. Has anyone experimentally tested the 800 Mbits/sec claimed transfer rate and with what file size megabytes or gigabytes (as typically would be used in real situations)? It seems quite high considering flash chips only support about 320 Mbits/sec sustained (under the most favorable addressing mode scenarios.

  2. As far as I’m aware Sony claims 800MBits/sec not 800Mbytes/sec so that’s 100Mbytes/sec, quite a reasonable claim really, and one I have seen from the gear.

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