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Lifewire / Jonno Hill
4K-capable on some cameras
Middling UHS-1 speeds
The Lexar Professional 633x 256GB SDXC Card offers middle of the road performance at a very attractive price that makes it worthy of consideration.
The Lexar Professional 633x 256GB SDXC Card was neither the fastest nor the slowest among the best SD cards that we tested. It did manage to live up to the minimum write speed classifications listed on the card, but not too much beyond this. Nevertheless, this card is fast enough to handle 4K video recording across most mirrorless cameras on the market today. Is it enough to make the cut though, or should you look elsewhere?
The Lexar Professional 633x 256GB SDXC Card features a black sticker with a bronze trim on the side, where the advertised speed of 95 MB/s and 633x are shown. Lexar has adopted a color scheme for its cards, where bronze is rated at less than 1000x, silver is 1000x+, and gold is 2000x. Most manufacturers don’t use Lexar’s speed grading scheme of these large numbers followed by a multiple, but for those curious, it’s a representation of how much faster the speed is compared to a CD-ROM drive speed of 150 KB/s. Perhaps you can see why most companies don’t find this to be a particularly relevant standard of measurement anymore.
It did manage to live up to the minimum write speed classifications listed on the card, but not too much beyond this.
The Lexar Professional 633x 256GB SDXC Card card is simple to begin using, as you would have probably guessed. Simply remove it from its packaging and insert it into your device to begin using.
The Lexar Professional 633x 256GB SDXC Card came into second to last in our write speed tests. This might not be an encouraging statement, but it’s also not the end of the world for most shoppers. If you use this card primarily for video capture, the speed offered by this card is likely sufficient, but let’s take a closer look at the results.
We tested sequential write speeds in CrystalDiskMark using a 1 GiB test over 9 repetitions. The Lexar Professional 633x 256GB SDXC Card registered 44 MB/s in this benchmark. Next, we performed a similar test using Blackmagic Disk Speed Test using the 5 GB stress test. In this test, the Lexar only managed 30 MB/s. This is a bit too close for comfort to the floor of the U3 speed standard, but it does pass.
Read speeds were right in line with just about every other UHS-I card we tested. The Lexar Professional 633x 256GB SDXC Card showed 89 MB/s in CrystalDiskMark and 93 MB/s in Blackmagic’s test.
To put these numbers in perspective, even if this card only managed the 30 MB/s we saw in our worst test, it would still be able to record video using the highest bitrates required for 4K capture by the Sony A7R IV, or Panasonic Lumix GH5. All this to say that while this card isn’t winning any awards on speed, it will still serve many users without incident.
The Lexar Professional 633x 256GB SDXC Card costs just $40, a veritable bargain for its 256 GB. This works out to just $0.15/GB, the cheapest among the cards explicitly tested in our roundup. If you need a lot of storage and don’t have a lot to spend, this card will naturally float to the top of your list.
Polaroid makes one of the fastest UHS-I cards in our tests. Their 64 GB card recorded between 51 and 74 MB/s in CrystalDiskMark and Blackmagic Disk Speed Test respectively. This makes it faster than the Lexar even on its worst day. However, at $0.51/GB, the Polaroid costs nearly as much as the Lexar despite being 1/4th the capacity.
Adequate performance at a bargain price.
The Lexar Professional 633x 256GB SDXC Card isn’t fast enough to get any extra attention, but it delivers enough performance to give the average user everything they need to get the job done. This card is one good sale away from being the best card for the money, but currently sits just shy of being the top recommendation.