Sometimes the best is overkill. SanDisk’s new UHS-I Extreme Pro Memory Card ($299.99) is the fastest microSD card we’ve tested. But I’m unconvinced that this bleeding edge performance justifies the extra cost, especially in mobile devices. While speed freaks will adore this card, most ordinary users will wonder what the fuss is about.

Memory cards are used to pump up the storage in many phones and tablets. SanDisk’s Pro line is also heavily promoted for use in high-res action cameras and digital cameras that record 4K video. Right now, 64GB is the largest mainstream size for these chips; while we’re starting to see 128GB cards, they cost a real premium.

SanDisk has several lines of microSD cards. We’ve tested the Ultra, Extreme, Extreme Plus and Extreme Pro. The Pro is the fastest. 

The SanDisk Plus and Pro cards are the first cards we’ve seen with a UHS Class 3 speed rating. According to the SD Card Association, that means they’re capable of 4K video. SanDisk claims transfer speeds on the Pro cards of up to 95MBps.

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To test microSD cards, we ran the A1 SD Card benchmark on a Samsung Galaxy Note 3 ($307.96 at Amazon)(Opens in a new window) smartphone, copied files to and from a MacBook Pro using the built-in SD card reader, and ran the CrystalDiskMark benchmark on a Cyberpower PC with the cards plugged into a USB 3.0 reader.

As you can see, the Galaxy Note 3 couldn’t take advantage of any speeds faster than the Mobile Extreme card. The Pro showed some advantage on read speeds, and definitely some advantage in random reads and writes. But random reads and writes are rarely used with SD cards—they’re more commonly used when you’re running applications or an operating system off a drive, not storing media files.

The question then becomes whether the limited extra speed is worth the big jump in price. SanDisk tends to have completely silly list prices for its memory cards; this card lists at $299.99, which would make it a one-star product for being absurdly expensive. But SanDisk themselves pointed out to us it’s selling for $99.99 on Amazon.

That’s still almost double the price of SanDisk’s Mobile Extreme card, which also offers excellent performance. We’ll leave our Editors’ Choice award with the Mobile Extreme card for the best balance of price and performance in the microSD card space.