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Home » Reviews » Storage Drives » Lexar 633x 64GB MicroSDXC UHS-I/U3 Review

Lexar 633x 64GB MicroSDXC UHS-I/U3 Review

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Storage drive has become one integral part of our daily lives, specially for those who use and store digital files. Storage drives comes in different sizes and capacities. Today we are going to look at one of Lexar’s microSD card – the Lexar 633x 64GB microSDXC UHS-1/U3 (Class 10) LSDMI64GBSBNA633R. The Lexar 633x microSD is a small portable storage solution primarily used in mobile devices like smartphones, tablets and even digital cameras. The 633x series are available in four difference capacities; 16Gb, 32GB, 64GB and 128GB. What we have here is the 64GB capacity. Before we proceed, I’d like to thank Lexar for providing the sample for the purpose of this review.

Lexar 633x 64GB MicroSDXC UHS-I U3 Review

Lexar 633x 64GB microSDXC Review

Before I begin, I’ll just give some information for those who are still lost or have no idea regarding the terminologies or those numbers and letters you see on memory cards.

microSDHC – This basically means Micro Secure Digital High Capacity. Usually SD cards with capacities 32GB and below.
microSDXC – This means Micro Secure Digital Xtended Capacity, ranging from 64GB up to 2TB.
UHS – Ultra High Speed
UHS-I / UHS-II – Refers to the bus speed, UHS-I has a bus speed of 50MB/s up to 104MB/s. While UHS-II has a bus speed of 156MB/s up to 312MB/s.
U1 / U3 – Indicates the minimum serial data writing speed. U1 has a minimum of 10MB/s, while U3 has a minimum of 30MB/s. This is usually used in memory cards with UHS Speed Class.
Class 10 – Indicates that the card has a minimum performance speed of 10MB/s. This is usually used in memory cards with (High and Normal) Speed Class.

*You can read more about these from

The Lexar 633x is basically a high performance Micro Secure Digital Xtended Capacity card with Ultra High Speed class having a speed of up to 95MB/s. It’s basically designed for smartphones, tablets, sports camcorder and digital cameras that uses microSD card for storage. Since it has a rated speed of up to 95MB/s, it’s an ideal storage solution for 1080p full-HD, 3D and 4K video capture, high resolution photos and even media files. The company is so confident with the product that they are offering a lifetime warranty for the card.

The Lexar 633x microSD card series also comes with a handy USB 3.0 card reader. Most of the storage companies usually advertise their memory cards with speeds of up to 60MB/s or 95MB/s or even up to 280MB/s. But that doesn’t mean that both the read and write speeds are on the same speed rating. And that’s one thing we are going to find out in this review – the card’s actual performance.

I haven’t tried the lower capacities (16GB and 32GB microSDHC 633x), but based on experience, higher capacities tend to have a better read/write speed compared to the SD cards with lower capacities. Below are photos of the packaging of the Lexar 633x. Conveniently, it comes with a USB 3.0 reader so that you can easily connect the microSD card to any computer via USB. This is really useful specially if you don’t have any card readers.

Lexar 633x microSDXC UHS-I 64GB Review-01 Lexar 633x microSDXC UHS-I 64GB Review-02

You can read some of the features of the Lexar 633x from the packaging.

Lexar 633x microSDXC UHS-I 64GB Review-03 Lexar 633x microSDXC UHS-I 64GB Review-04 Lexar 633x microSDXC UHS-I 64GB Review-05

The 64GB microSDXC itself is protected by a small case. It is best that you keep the microSD inside the small case when not in use.

Lexar 633x microSDXC UHS-I 64GB Review-06 Lexar 633x microSDXC UHS-I 64GB Review-07

Above are close up photos of the Lexar 633x 64GB microSDXC. You can see the symbols for USH-I, Class 10 and U3 in front of the card. I’m not sure if Lexar’s 633x are water proof, temperature proof, shock proof or even X-ray proof because I can’t find any information regarding its protection or durability. It’s not indicated on the packaging and even from the official page.

Lexar 633x microSDXC UHS-I 64GB Review-08 Lexar 633x microSDXC UHS-I 64GB Review-09

Here are photos of the included micro SD USB 3.0 card reader. It’s small and doesn’t have any LED indicator. It can also be used to with other microSD cards.

Testing and Benchmarks

Lexar 633x microSDXC UHS-I 64GB Review-10 Lexar 633x microSDXC UHS-I 64GB Review-11

In testing the Lexar 633x 64GB MicroSDXC, I used the included card reader and plug it in my test bench. I also used a third party card reader just to check if there is any performance difference. I used ATTO Disk Benchmark tool, HD Tune Pro, CrystalDiskMark, and Anvil’s Storage Utilities to benchmark the microSD card’s performance. I also used TeraCopy to benchmark its actual performance while transferring files to and from the microSD card. Below are the results:

ATTO Disk Benchmark

Lexar 633x ATTO Benchmark

HD Tune Pro 5.50 Benchmark

Lexar 633x HD Tune Pro Benchmark

CrystalDiskMark 3.03 (32-bit and 64-bit)

Lexar 633x CrystalDiskMark Benchmark

Anvil’s Storage Utilities

Lexar 633x Anvil Storage Compressible Benchmark

Lexar 633x Anvil Storage Partial Benchmark

Lexar 633x Anvil Storage Incompressible Benchmark

If you take a look at the benchmark results of the Lexar 633x microSDXC using Anvil’s Storage Utilities, you will notice that its read and write speeds remain closely constant regardless of the file type. It performed similar whether the file is compressible or incompressible. There are storage drives, specially SSD, where write performance tends to decline with incompressible files.

Copy test SSD to Lexar 633x Copy test Lexar 633x to SSD

Above are screenshots of TeraCopy when I tried to copy files coming from my SSD to the Lexar 633x. The files I copied are RAW images from my Nikon D7100. The screenshot on the left shows transfer status from my SSD to the Lexar 633x. Meanwhile, the screenshot from the right shows the files are transferred from the Lexar 633x back to my SSD. As expected, it’s much faster to access files from the 633x, compared to writing on the microSD card.

Lexar 633x microSDXC USH-I 64GB with Kingston MobileLite G4 Card Reader

Below are benchmark results of the Lexar 633x microSDXC using a third party card reader, the Kingston MobileLite G4.
Lexar 633x ATTO Benchmark with Kingston MobileLite G4

Lexar 633x HD Tune Pro Benchmark with Kingston MobileLite G4

Lexar 633x CrystalDiskMark Benchmark with Kingston MobileLite G4

Lexar 633x Anvil Storage Compressible Benchmark with Kingston MobileLite G4

Lexar 633x Anvil Storage Partial Benchmark with Kingston MobileLite G4

Lexar 633x Anvil Storage Incompressible Benchmark with Kingston MobileLite G4

Based on the results I got the read and write performance remains the same, with just a very slight difference. It’s safe to safe that its read performance is around 90MB/s and its write performance is just around 45MB/s which is around half its read speed.

Price and Availability

addtocartThe Lexar 633x microSDXC UHS-I is very much available right now. The manufacturer’s suggested retail prices are as follows: $33.99 for 16GB, $50.99 for 32GB, $93.99 for 64GB and $159.99 for 128GB. But you can get it for a much lower price from B&H here. At the time this review was published, B&H is selling the Lexar 633x with the following retail prices: $23.95 for 16GB, $29.99 for 32GB, $44.99 for 64GB, and $119.95 for 128GB. There are also dual pack as well (2 microSDs in 1 pack). It comes with limited lifetime warranty for the microSDXC card and limited 1-Year warranty for the USB 3.0 reader.

Lexar 633x 64GB microSDXC Review: Conclusion

The Lexar 633x 64GB microSDXC looks like a very competitive microSD card. It remained very close to its advertised speed, At least for the read speed. Its actual write speed is just half of its read speed. With that kind of performance, you can safely shoot full HD 1080P videos or even high resolution photos. Although I haven’t tried shooting it with 4K since we currently do not have any 4K capable digital camera in our lab. The included USB 3.0 microSD card reader is a plus factor as well, since some (or most) companies do not include a card reader.

It would be great if Lexar could indicate how durable the Lexar 633x or certify whether the card is resistant or proof against certain conditions or environment. Other than that, I think the Lexar 633x is a very capable microSD with very competitive pricing (street price). When shopping for a microSD, this should make your list shorter.


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I love computers since I was a kid. I’m always fascinated with new technology, especially in the PC world. Many years ago, I was curious if the reviews I read were true and real. So, why not test them myself and share my first-hand experience? And thus, here we are. Thanks for reading!

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