Is it really a USB 3.0 flash drive?

According to the USB 3.0 / USB SuperSpeed specification, USB 3.0 has a target read-data transfer rate of 5 gigabits per second (Gbps) -- that's equivalent to 640 megabytes per second (MBps).  By contrast, USB 2.0 has three target read-data transfer rates, the upper limit being 480 megabits per second (Mbps) -- 60 MBps.

Roughly speaking, you'd expect a USB 3.0 drive to perform at about 10x that of a USB 3.0 drive.  Well, at least in the specs, you would; everyone knows that in the real world, specs never match actual performance, and the USB 3.0 specifications infer a throughput maximum of 400 MBps, instead of the 640 MBps -- still pretty fast.

So what should one think, when manufacturers list the speeds of their USB 3.0 flash drives at or below the 60 MBps speed?  Is it really a USB 3.0 flash drive, if its speed is less than the target specification for a USB 2.0 flash drive?

To demonstrate this point, here's a sample of some 8GB / 16GB USB 3.0 flash drives on Newegg:

• Team SR1 8GB USB 3.0 Flash Drive (Red) Model TG008GSR1R3 / up to 55 MBps
• Team Color Turn 8GB USB 3.0 Flash Drive (Purple) Model TG008GE902V3 /  up to 54 MBps
• Patriot Supersonic Xpress 8GB USB 3.0 Flash Drive Model PSF8GXPUSB / up to 50 MBps
• Mushkin Enhanced Ventura 8GB USB 3.0 Flash Drive Model MKNUFDVT8GB / up to 50 MBps
• Wintec FileMate 16GB USB 3.0 Flash Drive Model 3FMSP02U3SL-16G-R / up to 45 MBps

Embarrassing, no?  Maybe even deceptive, or false advertising, to call these drives USB 3.0.  Sure, they have the right port hardware, but they sure don't look that fast.

When you move up to the very large flash drives - 64GB - things dramatically change:

• Mushkin Enhanced Ventura Pro 64GB USB 3.0 Flash Drive Model MKNUFDVP64GB / up to 120 MBps
• CORSAIR Flash Voyager GT 64GB USB 3.0 Flash Drive Model CMFVYGT3-64GB / up to 135 MBps
• Patriot Supersonic Magnum 64GB USB 3.0 Flash Drive Model PEF64GSMNUSB / up to 200 MBps
• Kingston HyperX DataTraveler HyperX 3.0 64GB USB 3.0 Flash Drive Model DTHX30/64GB / up to 255 MBps

Big difference in performance.  The Kingston HyperX DataTraveler and the Patriot Supersonic Magnum are respectable, with write-data speeds faster than the Mushkin Enhanced Ventura Pro's read-data speed, and read-data speeds that are double.   But it'll cost ya.

So the moral of the story is: buy a big flash drive if you want speedy performance (even if you're not using a whole lot of data) and never rely on the USB 3.0 moniker to discern the true speed of a device.