Subject: Storage | October 13, 2015 - 09:24 AM | Allyn Malventano
Tagged: XQD, SD, microSD, Lexar, flash, CFast
Lexar (Micron's portable media brand) is known for their versatile flash media readers and lines of portable flash memory products. Today they have updated two of their big SD Card lines. First up is their 2000x (300MB/s) product, which now comes in a 128GB capacity:
As we pointed out in our SD Card Speed Classes, Grades, Bus Modes, and File Systems Explained piece, cameras and video recorders most likely won't use that super high 250MB/s write speed, but emptying a 128GB card at 300MB/s will take only 7 minutes (provided your destination device can write that fast)! This model comes with a small USB 3.0 reader, which makes sense as most systems can't hit 300MB/s with their built-in readers!
Next up is a HUGE capacity introduced in their 633x line:
This model may be less than half the speed of the 2000x part above, but 95 MB/s is not too shabby considering this card can store a half a TB! Write speeds are a bit more limited as well, coming in at 45MB/s. The use case for this card is as a full-time backup slot for capable SLRs, or more commonly (I believe) as a semi-permanent secondary storage addition to Ultrabooks. The cost at $0.54/GB comes in far less than the internal storage upgrade prices of many laptops.
Lexar also updated their CFast lines with faster (3500x / 3600x) models, as well as their XQD lines (1400x / 2933x). Lastly, the Professional Workflow XR2 (XQD 2.0) and UR2 (microSD UHS-II) pods are now available.
Stand by for a review of the 633x 512GB SD Card as we have one in for testing!
What you never knew you didn't know
While researching a few upcoming SD / microSD product reviews here at PC Perspective, I quickly found myself swimming in a sea of ratings and specifications. This write up was initially meant to explain and clarify these items, but it quickly grew into a reference too large to include in every SD card article, so I have spun it off here as a standalone reference. We hope it is as useful to you as it will be to our upcoming SD card reviews.
SD card speed ratings are a bit of a mess, so I'm going to do my best to clear things up here. I'll start with classes and grades. These are specs that define the *minimum* speed a given SD card should meet when reading or writing (both directions are used for the test). As with all flash devices, the write speed tends to be the more limiting factor. Without getting into gory detail, the tests used assume mostly sequential large writes and random reads occurring at no smaller than the minimum memory unit of the card (typically 512KB). The tests match the typical use case of an SD card, which is typically writing larger files (or sequential video streams), with minimal small writes (file table updates, etc).
In the above chart, we see speed 'Class' 2, 4, 6, and 10. The SD card spec calls out very specific requirements for these specs, but the gist of it is that an unfragmented SD card will be able to write at a minimum MB/s corresponding to its rated class (e.g. Class 6 = 6 MB/s minimum transfer speed). The workload specified is meant to represent a typical media device writing to an SD card, with buffering to account for slower FAT table updates (small writes). With higher bus speed modes (more on that later), we also get higher classes. Older cards that are not rated under this spec are referred to as 'Class 0'.
As we move higher than Class 10, we get to U1 and U3, which are referred to as UHS Speed Grades (contrary to the above table which states 'Class') in the SD card specification. The changeover from Class to Grade has something to do with speed modes, which also relates with the standard capacity of the card being used:
U1 and U3 correspond to 10 and 30 MB/s minimums, but the test conditions are slightly different for these specs (so Class 10 is not *exactly* the same as a U1 rating, even though they both equate to 10 MB/sec). Cards not performing to U1 are classified as 'Speed Grade 0'. One final note here is that a U rating also implies a UHS speed mode (see the next section).
Introduction, Specifications, and Packaging
Lexar is Micron’s brand covering SD Cards, microSD Cards, USB flash drives, and card readers. Their card readers are known for being able to push high in the various speed grades, typically allowing transfers (for capable SD cards) much faster than what a typical built-in laptop or PC SD card reader is capable of. Today we will take a look at the Lexar ‘Professional Workflow’ line of flash memory connectivity options from Lexar.
This is essentially a four-bay hub device that can accept various card readers or other types of devices (a USB flash storage device as opposed to just a reader, for example). The available readers range from SD to CF to Professional Grade CFast cards capable of over 500 MB/sec.
We will be looking at the following items today:
- Professional Workflow HR2
- Four-bay Thunderbolt™ 2/USB 3.0 reader and storage drive hub
- Professional Workflow UR1
- Three-slot microSDHC™/microSDXC™ UHS-I USB 3.0 reader
- Professional Workflow SR1
- SDHC™/SDXC™ UHS-I USB 3.0 reader
- Professional Workflow CFR1
- CompactFlash® USB 3.0 reader
- Professional Workflow DD256
- 256GB USB 3.0 Storage Drive
Note that since we were sampled these items, Lexar has begun shipping a newer version of the SR1. The SR2 is a SDHC™/SDXC™ UHS-II USB 3.0 reader. Since we had no UHS-II SD cards available to test, this difference would not impact any of our testing speed results. There is also an HR1 model which has only USB 3.0 support and no Thunderbolt, coming in at a significantly lower cost when compared with the HR2 (more on that later).
Subject: General Tech, Storage | May 5, 2011 - 06:05 PM | Scott Michaud
Tagged: mod, microSD, atari 810
It is common knowledge that technology gets smaller as time advances. There is, however, a point where a certain level of advancement trots along the border to absurdity and makes you think about exactly what is possible with modern technology and occasionally an innovative spirit. Leave it to the hackers to consistently push that boundary and entertain the rest of us less talented individuals.