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The Best USB 3.0 Flash Drive | The Wirecutter
After more than 14 hours of new research and testing, we found that
 the 64 GB SanDisk Extreme CZ80 USB 3.0 Flash Drive is still the best flash drive for most people.

64 GB flash drives

SanDisk SDCZ880-128G-G46 Extreme Pro 128GB USB 3 $80 
289 MB/s read (wireCutter) 420MB/s (Amazon)

Sandisk Ultra USB flash drive, 64 GB, Black (SDCZ48-064G-A46) USB 3  4.2  $20
up to 130MB/s read

SanDisk Cruzer CZ36 64GB USB 2.0 Flash Drive, USB 2 $16

SanDisk Ultra Fit 64GB USB 3.0 Flash Drive (SDCZ43-064G-GAM46) $15
Read speeds up to 150MB/s

When to buy a flash drive, an external hard drive, or an external SSD | PCWorld
My quick answer: Use an external hard drive for backup. Use a flash drive or an SSD if you want to move files from one computer to another and a network isn’t practical.

The long answer: It all depends on how much storage you need, how much you worry about physical damage, and how much you’re willing to spend. Flash-based storage such as external SSDs or flash drives (also known as pen drives or thumb drives) tend to be more robust: Drop one to the ground, and it’s still likely to work. But hard drives provide more storage for the dollar.

My tests reading a 18 GB file
64 GB SanDisk Ultra Fit USB 3.0 - 152 MB/s
1 TB WD Passport USB 3.0 - 94 MB/s

2 GB 4 GB 8 GB 16 GB 32 GB
(Hi-def movie recording MPEG-4. H.264)
Fine mode (13Mbps/CBR) 20 min. 40 min. 80 min. 160 min. 320 min.
Normal mode (9Mbps/VBR) 30 min. 60 min. 120 min. 240 min. 480 min.
Economy mode (6Mbps/VBR) 45 min. 60 min. 180 min. 360 min. 720 min.
10 Megapixels, 3648x2736, Fine mode 770 photos 1,540 photos 3,080 photos 6,160 photos 12,320 photos
ACC, MP3 HQ mode, 128Kbps 34 hr. 7 min. 68 hr. 14 min. 136 hr. 27 min. 272 hr. 54 min. 545 hr. 48 min.
Cards | USB Flash drives
Type Size Compatibiity
SD Secure Digital 128MB-4GB Canon PowerShot, Pentax, Nikon, Palm (newer)
SDHC SD High Capacity 4-32GB
mini SD miniSecure Digital 128MB-2GB Cell Phones
micro SD microSecure Digital 128MB-2GB Cell Phones
MMC Multi Media Card   Canon PowerShot
CF-I CompactFlash I 128MB-8GB Canon EOS & Digital Rebel, Olympus, old Nikon, old Palm and Pocket PCs
CF-II CompactFlash II 128MB-8GB Microdrive, Olympus
xD xD Picture Card 64M-1GB Fuji, Olympus
MS Memory Stick Pro 512MB-4GB Sony
Memory Stick Duo Pro 256MB-2GB Sony
SM Smart Media 128MB Fuji, old Olympus
Other types of cards:
SIM - Subscriber Identity Module for mobil phones
Smart card or or integrated circuit card (ICC) (ISO 7810 and 7816 Card Standard)
  Credit Card with imbedded ICC.
PC Card - PCMCIA - 85.6 mm long and 54.0 mm wide

Type Size TransferRate Price
SanDisk Secure Digital
Extreme III 1GB 20MB/sec $140
Extreme III 12GB 20MB/sec $780
Extreme III 16GB 20MB/sec $1050
Ultra II 1GB 10MB/sec $80
Standard 1GB 2MB/sec $50
Ultra II 2GB 10MB/sec $120
Standard 2GB 2MB/sec $100
Transend Secure Digital
High Speed 4GB 22MB/sec $220
Note: Above types are SanDisk names; other manufactures use terms like High Speed or Extreme Performance for faster cards.
There is a brand name Ultra who's basic card is a 40X write speed. Price a/o Mar. 2006
Transfer Rate 2006
13X 2MB/sec
60X 9MB/sec
66X 10MB/sec
133X 20MB/sec
150X 22.5MB/sec
Micro SD - Class rating
Any Micro SD card 4GB and above are SDHC (High Capacity).
Class is an minimum non-fragmented sequential write speed. Used for device compatibility. The X rating to the left is the maximum speed.
Speed Class Minimum transfer speed Logo Recommended Uses
Class 0 Legacy. No speed rating. n/a Backing up, transferring and storing photos, music and other files.
Class 2 2 MB/s File storage, SD video recording.
Class 4 4 MB/s File storage, SD and HD video recording
Class 6 6 MB/s File storage, SD and HD video recording.
Canon T1i 500D
Class 10 10 MB/s HD video recording, HD still consecutive recording.
Nikon D90
UHS-I 10 MB/s Large size HD video recording, high quality video capture for real-time broadcasts (i.e. HD TV shows)
Source: How to Choose an SD Card for Best Performance and Compatibility
See: A 2009 discussion about microSD card speeds- xda-developers forum
Android will read up to 32 GB
Read Speed of a Standard CD-ROM = 1.2MB/s One forum comment said, "As an example I've written HD video from the camera to a 16GB Sandisk Ultra Mobile, 16GB Class 6 Transcend & 32GB Sandisk Class 2 and there's no speed difference in writing/playing back the video file.
The only place you will see any speed differences is when transfering data from a PC to the card."
These speed notations may not be consistent among manufactures.
Write speeds are slower than read speeds.

Most camera manuals don't tell you what speed of flash card you should buy, usually recommending a type and maybe a manufacturer (who has often paid to be included in their recommended list). If your camera has resolution under five mega pixels, the speed rating of the flash card won't matter much. In fact many cameras will not work well with ultra high speed cards of 66X and 150X speeds because of the special formatting used to achieve these high speeds. The improvement you are likely to see in a higher rated card will be minimal and undetectable.

Professional photographers using professional-grade cameras should use high-speed flash (40X [Class 6] - 66X [class 10]). If your camera has a pixel rate more than five mega pixels, you will benefit from a flash card with a higher speed rating. If your camera has a resolution less than five mega pixels, simply use cards rated less than 40X, this way you can ensure compatibility and not spend money unnecessarily on higher rated cards.

Secure Digital (SD):
Secure digital cards or SD card for short, is a derivative of the now widely used Multi media (MM) cards. The SD's data transfer rate is up to 10MB/sec, which is four times faster than the MM cards.
The outstanding feature of SD cards is that, it is in compliance with SDMI or Secure Digital Music Initiative. This feature of the card will not allow for example, a copyrighted music to be downloaded from any source. Almost all electronic manufacturers are coming up with products, which support the SD cards hoping this would be the next big thing in memory cards. Products, which support SD cards, are almost backward compatible with MM Cards but not the other way around.

SanDisk Ultra II Plus SD Card can be folded to fit directly in a USB port. 1G = $90

CompactFlash (CF) cards provide complete PCMCIA-ATA functionality and compatibility and can be used in a PCMCIA slot with an adapter.
A Microdrive is a CF Type II card and can go up to 4GB.
CF Type I thickness is 3.3 mm; CF Type II thickness is 5 mm
The CompactFlash card specification version 3.0 supports data rates up to 66MB/sec and capacities up to 137GB.

which brand of class 6, 16GB microSD should i get? - Android Forums, says,
Pkopalek: I specifically avoided Transcend because of reader reviews and speed tests.
Frisco: I just googled "Transcend microsd card reviews" and found one negative among dozens of positive reviews.
We use transend at our facility, including over 600 monitoring devices and nearly two thousand special paging units; never a glitch, memory loss or degradation of data in years of duty. Pkopalek: I read that the RiDATA's get RMA'd a lot more often, and speed comparison tests that put either at a high rate of speed, and either at a low rate of speed.
I also read comparisons that put the SanDisk (and other much more well known brands) Class 4 FASTER than the other brands' Class 6.
Frisco: Transcend, SanDisk and Lexar pan out over the long haul to be the fastest, most reliable of the microsd cards for devices such as cell phones and other sensitive equipment.

32GB USB flash memory sticks (thumb drives), now available at $120, are an alternative for backup.
Listed Data Transfer Rate are 19MBps Read 13MBps Write
Actual for a 32GB flash stick are:
	               Sequential Read       Write
32 GB Corsair Flash Voyager 22 MB/sec  10 MB/sec
32 GB OCZ Rally 2           30 MB/sec  22 MB/sec
32 GB Patriot Xporter XT    31 MB/sec  17 MB/sec
Actual report on Amazon for OCZ OCZUSBATV32G 32GB ATV USB:
2.5MBps write (3-5 hrs for 25GB) for a lot of small files. Large files copy faster.
When I formated it as a DOS (Fat32) disk it wrote at about 1.5 MB/sec
When I formated it as Mac OS Extended (Journaled) and was about 2 MB/sec.
A 2GHz dual processer Mac Pro gave 4 MB/sec
When I partitioned a 32GB OCZ ATV into 2 FAT32 partitions and copied from a Mac PowerBook G4 wuih USB 2.0 it 2 hrs to copy 350 MB. 0.05 Mb/sec.
On a PC witn Win 2K: Read Write OCZ 32G 0.97 MB/s 0.59 MB/s Cruzer 4G 0.97 MB/s 0.94M B/s Windows will not read more than one partition on a removable drive.
You can get software to flip the removable drive bit so it will work.
USB 2 was reported to be slower on Macs (may be improved in panther OS X 10.3)
See: X-Bit Labs rreview of 32 GB USB flash drives:

Formatting - File Systems:
Most SD cards come pre-formatted on an MBR partition scheme. SD cards will usually be FAT 16*, SDHC cards will be FAT32 and SDXC cards are usually exFAT, but you can reformat them.

Note that you can use any disk utility to format SD cards, such as Gparted or the disk utilities built-in to Windows or OS X. But the SD Association recommends using their own SD Formatter to avoid formatting the “Protected Area” that exists on some SD cards that incorporate security features.

File Systems
Flash USB (thumb) drives
Speed Tests at MobileTechReview.com
Reviews and FAQ: Memory Cards at MobileTechreview.com

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last updated 3 Nov 2006