Kinda Disappointed in Lexar 600x

When I saw the Lexar Pro 600X 64GB SDXC UHS card on sale at Amazon for $42 I jumped at it. These are usually over $100. The Lexar website has a MSRP of $169


From their website: "Lexar® Professional 600x SDHC™/SDXC™ UHS-I cards let you quickly capture and transfer high-quality photos and 1080p full-HD, 3D, and 4K video, with a read transfer speed up to 600x (90MB/s).*" The * means "*Up to 90MB/s read transfer, write speeds lower. Speeds based on internal testing. Actual performance may vary."

SEE: Lexar® Professional 600x SDHC?/SDXC? UHS-I cards | Lexar

And boy did my performance vary. I am using this on a USB 3.0. I also have a SanDisk Extreme card which says 45 MB/s and delivers about that. But this new card, nowhere near 90MB/s - it does a wee bit better than the SanDisk Extreme running in the 50's - or just over half of what they advertise.



I did test it a couple of time. Formatted the card both on my PC and on the camera. Performance is constant. First wee bit - it goes great guns, (see hump at the left) but then it drops down to about 30-60 MB/s. Anyone else use Lexar and see this kind of performance?

Did I get a bad card? Maybe that's why it was on sale for such a discounted price?

But I suppose I got a 64GB card that does out perform (ever so slightly) the SanDisk Extreme, and $42 is a good price for that.

When the Extreme Pro's come down a bit or go on sale I'll pick up one of them to compare.

I have the same card and used it for my D800e since it was on sale. I am not overly critical since it is a bargain and is much faster than my Lexar 133x that I purchased a couple of years ago.

I prefer using my CF cards since they perform much faster at 1000x.


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What were you copying to? Your slowdown may have been caused by something other than the card. The hump to the left shows that it is capable of higher speeds. The thing is the card manufacturers never state whether that is a "burst" speed or a sustained speed. Try copying just a couple of images and see what you get for a speed.

Data transfer speeds are limited by whichever is slower, the read speed of the source or the write speed of the target. High speed bursts at the beginning are usually caused by cache somewhere in the pipe.

I was writing to a Seagate SATA III Harddrive - it is on a 6GB/s SATA port on my motherboard which supports much faster data transfer than the USB 3.0 and SD card hard to imagine the bottleneck is on the PC side.

I am curious about that initial burst speed and perhaps they measure these things by averaging the burst speed at the beginning with the rest - but that burst only lasts for a short time.

It was only 7 GB transfer on a 64GB card or about 10% of the capacity, if it can only manage to transfer less than 10% of its capacity at the advertised speed that's odd - and again my ScanDisk never displayed this sort of transfer speed variance.

I'll do a couple more tests and try to learn a little more about how they measure these things.

Port speed is meaningless. The write speed of the hard drive is usually the limiting factor. An SD card can read data a lot faster than any hard drive can write data. Hard drives will have a burst IO rate due to the small amount of cache on the drive. Remember too that the card manufacturers say "up to". No guarantees on sustained rates.

Decided to do some "real world" comparison testing. Using the same set of images - this lot was about 5GB 134 files.

Started with my Kingston Class 10 It is much slower.

Hard disk to Card was about 11MB/s for the Class 10 and about 33MB/s for both the Lexar Pro and the ScanDisk Extreme.

The real test was from the SD to the HD

Class 10 was slowest at just under 30 MB/sec - but look at that big hump of fast transfer in the beginning - ???
+

Then the ScanDisk Extreme at about 49 (it has been consistent at that level)



But wonder of wonders I retested the Lexar so that I could compare using the same set of files. And look



What to make of that?

Clearly the Lexar Pro is a faster disk.

Now my Class 10 is 32GB, ScanDisk is 16, For my second disk in my D610 do I want more capacity and use the 32GB of Class 10 or go for speed and use the ScanDisk? I suppose since my backup slot is for emergency over run I should use the 32GB eh?

David