Lexar High-Performance 633x MicroSDXC Review (1TB) – The First of Its Kind


Crystal Disk Benchmark is used to measure read and write performance through sampling of random data which is, for the most part, incompressible. Performance is virtually identical, regardless of data sample so we have included only that using random data samples.

Once again, we have very strong results in CDM and you might notice that the low 4K random results are low.  This is expected and typical of just about every flash card on the market today.  The reason is that these cards are intended to record, store and playback media which it does very well.  This is represented by the high sequential results on the first line.  If this card were fine tuned for very highly compressible and small system files, you might see those results on the bottom line just a bit higher.


The toughest benchmark available for solid state drives is AS SSD as it relies solely on incompressible data samples when testing performance. For the most part, AS SSD tests can be considered the ‘worst case scenario’ in obtaining data transfer speeds and many enthusiasts like AS SSD for their needs. 


These are actually very decent results through AS SSD as this software is one of the best in the business.  We didn’t waste our time with 4K testing, simply because it takes in excess of 20 minutes for a result that is low as we discussed in the previous benchmark.


Anvil’s Storage Utilities (ASU) are the most complete test bed available for the solid state drive today. The benchmark displays test results for, not only throughput but also, IOPS and Disk Access Times. Not only does it have a preset SSD benchmark, but also, it has included such things as endurance testing and threaded I/O read, write and mixed tests, all of which are very simple to understand and use in our benchmark testing.



The AJA Video Systems Disk Test is relatively new to our testing and tests the transfer speed of video files with different resolutions and Codec.



TxBench is one of our newly discovered benchmarks that we works much the same as Crystal Diskmark, but with several other features.  Advanced load benchmarking can be configured, as well as full drive information and data erasing via secure erase, enhanced secure erase, TRIM and overwriting.  Simply click on the title for a free copy.



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    Curious about the file system used: EXFAT? How does it handle NTFS, EXT4 (Linux format)?
    On a fast computer motherboard, it could handle RAID, both faster & safer than other systems, at lower power, vibration and heat consumption than the alternatives (HDD, SSD). As a storage medium for transportation (aircraft, buses, etc) blackboxes, it could hold a lifetime of reserved & stored data. Water-resistant & heat resistant as well.

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    I still can’t find a solution how to remove write protection from this 633 card.

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      How about warranty? I know of this happening now and then to other cards as well. It is unfortunate but that is why there is a warranty.

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