Believe it or not, we first heard of SDXC
nearly a year ago. Aside from a highly guarded chip
spotted at CeBIT, though, we've yet to see any of those cards in the flesh. Thankfully for the impatient among us, it seems as if the SD Specification 4.0 is well on its way to being hammered out, with the maximum data transfer rate scooting up from 104MB/sec to 300MB/sec. The actual scheme will also be changing from parallel to serial, with an unspecified amount of pins (more than 9, though) assisting in the speed increase. We're also told that the external dimensions of the cards will remain the same, and that backwards compatibility is of the utmost importance. We're guessing that newer cards will be able to rely on parallel transfers when used on older readers, while newer readers will accept data via the serial scheme; unfortunately, the nitty-gritty details have yet to be made public, but we're hoping for a serious coming-out party at next year's CES.
posted December 2nd 2009 2:24AM
hurry up with those 2tb flash cards!
Unbelievable!;)
We can hardly bare 1TB+ transferring at USB 2.0 speeds as it is. It's ridiculous to think that we would tolerate up to 2TB that transfers at least 25% slower. More storage capability is nice, but unless it can maintain that data for decades (which is about how long it'll take to fill and dump 2TB at those speeds), then I really don't see the point.
@Dante of the Inferno
Unless I'm mistaken, 300MB/sec is much faster than 480Mb/sec of USB 2.0. But your point remains, even at maximum speed transfering 2TB at that speed would be unpleasant.
@Dante of the Inferno
This is SD cards, not USB drives, and this speed might be useful for high-end cameras that internally write their data fast, like commercial HD video.
Of course reading it into the computer might be an issue and need some sort of lightpeak or SATA6 SD-card reader.
@Paul It's not that bad - about an hour per TB, which seems reasonable. Transferring photos from a full camera card (I'm talking 16GB not 2TB) can already take about an hour on my system, not all of which is transfer (a lot of processing involved in format conversion etc). At the end of a day's photography, waiting an hour is not that big a deal.
The 300MB transfer is probably an aspiration rather than reality - but so, certainly, is the 2TB, so it balances out...
@Dante of the Inferno
Due you aren't transferring it ALL AT ONCE. Its meant for portable devices not 1 TB pr0n collection backups.
@Dante of the Inferno
USB 2.0 Speed: 480Mbits/s = 60Mbytes/s
SD 4.0 Speed: 2400Mbits/s = 300Mbytes/s
So its is 5 times faster than USB 2.0. It also means that 1TB will transfer in less than 4 seconds.
@scyber
You need to check your math. It won't take under 4 seconds. It will take less than 4,000 seconds. 3,413 seconds to be precise. That is 57 minutes.
Also, no one has noticed that it is 2Tb (not bytes). This means it's 250GB. So it will only take 853 seconds or 14 minutes to transfer everything. This seems very reasonable to me.
@BuffaloX
Yep you're, right. It wasn't math error, b/c I was thinking 4000 seconds in my head, more likely a brain->typing hand communication error. Either way, that is way faster than USB 2.0.
omg, more than 9 pins!!!
@Spectracide I'm kind of wondering why going from parallel to serial requires MORE pins..
@(Unverified): Backwards compatibility.
If I understood it correctly, the post refers to the next gen of sd (after sdxc)? Which means it probably will not hit the market till 2012-3 :s.
Agree with Dante. Even filling up my 16gb micro sdhc takes an hour +. Good to see that they have worked on increasing the speeds but as capacity of the cards and our add levels grow it will need to be a whole lot faster than this to not be frustrating.
Cor blimey, you lot don't even know your are born. When I were a lad, we didn't 'av 16gb micro SD cards just lyin' around. If we wanted to transfer some information from one place to another, we had to write it down, longhand, on a roll of toilet paper.
my tiny, old-school brain goes pop when trying to understand how serial is faster than parallel.
@mrklaw Serial is faster than parallel because of "settling time". The number of logic gates (or variability in their manufacture) in a path for a given bit may not be the same as for another bit. As a result, the bits in a parallel connection will arrive at slightly different times. In order to accumulate a word of data, a settling time is required. The settling time imposes a maximum word transfer rate.
Serial data arrives one bit at a time, so there is no settling time. The upper bound on serial data is the switching time. Faster electronic / optical interfaces directly translate to faster serial transfer.
@macemoneta well, to be more precise, there's a kind of handover - when your technology is new and any one link is quite slow, you can get a speed benefit by parallelizing multiple links. For any given technology, there is a tipping point - when you can make a single link go at a certain speed, the issues macemoneta outlined become significant enough that parallelizing no longer gives you a benefit and instead starts slowing you down.
Why exFAT? Hopefully the new pin layout means that now is some sort of controller (SATA?) on the chip, that means future upgrades are easier.
Look at CompactFlash, still big due to having an onboard controller and using a standard bus (IDE/PATA).
@Pyronick
The file size limitation of FAT is an annoyance.
@Eternity: I mean, why a proprietary Microsoft-developed file system and not just something like Ext4 or a fork of it.
Closed-source software developers will eventually have to adapt to it, rather than open-source software developers not even getting a chance to adapt to it.
@Pyronick
I prefer the linux FS but the problem is getting existing operating systems to support native read and write for it. I'm assuming this "exFAT" has the same OS compatibility as FAT32.
Will this make it as fast as my SATA HDD?
@Jigen Nope. Just like mechanical hard drives cant reach the upper limit of SATA-III, neither will SD cards, not for a good while.
Interface speed is not equal to throughput. This means nothing, and I don't know why sites even bother reporting interface data rates. Unless the interface is a bottleneck, no one should even care.
When I bough a newer SD card I did not get the high capacity because the quick calculation in my head indicated the day long data transfer process required.
I want the 300MBytes/Second NOW!
I'm suprised that no one has picked up on the fact that the title for the article references 300MBps but the chart shows 300Mbps. There is a pretty substantial difference.
@imso919 Oh I see now. The chart says Mbyte/s. I'm more used to seeing MBps and Mbps to differential between the two. But since they're the same, there is nothing to differential. I suck!