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SanDisk Extreme Pro SD UHS-II Reader/Writer SDDR-399

SanDisk Extreme Pro SD UHS-II Reader/Writer USB 3.0 SDDR-399


The SanDisk Extreme Pro SD UHS-II SD Reader/Writer is a single-slot compact USB 3.0 SD card reader. It supports full-size SD and can operate in UHS-I and UHS-II modes.

The SanDisk reader is compatible with Max OS 10.3x+, Windows 7/8/10. It supports USB 3.0 and is backwards compatible with USB 2.0 connections. It is backed by a two year warranty. The reader tested is model SDDR-399-G46 UPC 619659146641. The reader is made in China.

Externally, the reader has a plastic case with brushed metal accent panel on top. There is a card access light on the top of the reader above the brushed metal panel. The ends and side of the reader and the slider are high gloss plastic while the top and bottom have a textured appearance. The reader has a lightweight and hollow feeling but is sufficiently rigid.

SanDisk Extreme Pro SD UHS-II Reader/Writer USB 3.0 SDDR-399 bottom

The body of the reader is tapered on the end next to the USB Type-A connector. Unlike the previous model SDDR-329 Extreme Pro UHS-II USB 3.0 reader, the SDDR-399 has no quirky slider. There is a single card slot on the end of the reader. The card slot on the reader tested for review was extremely tight to the extent that removing some SD cards was difficult. Some cards were comfortable snug while others were hard to remove even when using fingernails.

The reader measures 2.5 x 1.25 x 0.31 inches (64 x 32 x 8mm) including the USB plug. The reader is small but it may cause interference with USB ports located close together.


The SDDR-399 UHS-II reader was benchmarked with UHS-I and UHS-II SD cards. The highest benchmarks were 302.1 MB/s sequential read and 266.4 MB/s sequential write.

Using UHS-I cards the reader reached sequential benchmarks of 99.3 MB/s read and 94.7 MB/s write.

Reader: SanDisk Extreme Pro SD UHS-II Reader/Writer
Benchmark: CrystalDiskMark 3.0.3 x64
Program settings: 1000 MB, 5 passes, random test data
Operating system: Windows 8.1 Pro
Motherboard: Gigabyte GA-Z77X-UD3H
Processor: Intel Core i7-3770K @ 4.40GHz
RAM: 32GB DDR3 1600

SanDisk Extreme Pro SD UHS-II Reader/Writer
Card Benchmarks
SanDisk Extreme Pro 300MB/s UHS-II 64GB302.140247.685
SanDisk Extreme Pro UHS-II 275MB/s microSDXC 64GB290.143106.910
Transcend Ultimate UHS-II U3 64GB285.871182.838
Lexar Professional 2000x UHS-II 32GB283.055266.339
Lexar Professional 2000x UHS-II 64GB282.027264.792
Transcend Ultimate UHS-II U3 32GB281.648181.745
Sony SF-G 300MB/s UHS-II 32GB279.881254.632
SanDisk Extreme Pro 280MB/s UHS-II 32GB279.285230.938
Lexar Professional 1800x microSD UHS-II 32GB278.617231.295
Sony SF-G 300MB/s UHS-II 64GB278.211255.657
Delkin 1900x UHS-II 32GB277.18151.021
Sony SF-G 300MB/s UHS-II 128GB276.487253.985
Panasonic MicroP2 UHS-II 32GB275.00049.707
Sony M Series UHS-II 64GB268.93594.731
Toshiba Exceria Pro UHS-II 32GB261.002233.276
Lexar Professional 1000x UHS-II 32GB154.24886.041
Lexar Professional 1000x UHS-II 64GB152.85483.234
Lexar Professional 1000x UHS-II 128GB151.70486.673
SanDisk Extreme 90MB/s U3 64GB99.30649.688
SanDisk Extreme Pro 95MB/s 64GB99.30692.410
SanDisk Extreme 90MB/s U3 V30 64GB99.30654.204
SanDisk Extreme Pro 95MB/s 32GB99.30690.527
SanDisk Extreme Pro 95MB/s microSDHC 32GB99.29792.264
SanDisk Extreme Pro 95MB/s 128GB99.29792.085
SanDisk Extreme 90MB/s U3 V30 32GB99.29753.431
SanDisk Extreme 90MB/s U3 V30 128GB99.29765.717
SanDisk Extreme Pro 95MB/s 256GB99.29791.747
SanDisk Extreme Pro 95MB/s microSDXC 64GB99.29792.207
SanDisk Extreme Plus 95/90 MB/s U3 V30 microSDXC 128GB99.28890.433
SanDisk Extreme Plus 95/90 MB/s microSD 32GB99.28892.337
SanDisk Extreme 90MB/s U3 32GB99.28849.254
SanDisk Extreme Plus 95/90 MB/s microSD 64GB99.27892.126
SanDisk Extreme Pro 95MB/s U3 32GB99.27891.972
SanDisk Ultra 80MB/s 128GB99.27839.357
SanDisk Extreme 90MB/s U3 V30 microSDHC 32GB99.27870.488
SanDisk Extreme Plus 90MB/s U3 V30 32GB99.27866.797
SanDisk Extreme 90MB/s U3 V30 microSDXC 128GB99.26963.922
SanDisk Extreme Plus 95/90 MB/s U3 V30 microSDHC 32GB99.26990.857
SanDisk Extreme Plus 90MB/s U3 V30 64GB99.25965.426
SanDisk Extreme Plus 95/90 MB/s U3 V30 microSDXC 64GB99.25091.827
SanDisk Ultra 80MB/s 32GB Card 299.25020.706
SanDisk Extreme 90MB/s U3 V30 256GB99.25064.931
SanDisk Extreme 90MB/s U3 V30 microSDXC 64GB99.23170.845
SanDisk Ultra 80MB/s microSD 64GB99.20320.600
SanDisk Extreme 90MB/s microSDHC 32GB99.15648.935
SanDisk Ultra 80MB/s microSD 128GB99.14754.653
Toshiba Exceria UHS-I Class 3 32GB98.68060.611
Toshiba Exceria UHS-I Class 3 64GB98.67159.615
Samsung EVO Select microSDXC 256GB98.24687.156
Patriot EP Series microSDXC 64GB98.05377.546
Kingston U3 90/80 MB/s 64GB98.05386.076
Kingston U3 90/80 MB/s 32GB98.05389.416
Kingston Class 10 UHS-I 64GB98.04471.791
Kingston U3 (90/80) microSD 64GB98.03475.671
Panasonic Gold 95/90 64GB98.01677.175
PNY Pro Elite microSDXC 64GB98.01677.409
PNY Elite microSDXC 64GB97.97032.460
Lexar Professional 633x microSDXC 64GB97.97028.377
Lexar Professional 633x U1 32GB97.93421.744
Lexar Professional 633x U1 64GB97.90628.940
Transcend 600x 64GB97.89766.972
Patriot EP PRO microSDXC 64GB97.88876.903
Transcend 633x microSDHC 32GB97.88886.118
PNY Elite Performance U3 128GB97.88867.948
Gobe Magic 104MB/s 64GB97.87988.361
PNY Elite Performance U1 32GB97.87938.215
Transcend 95/60 MB/s U3 64GB97.87067.572
Transcend 95/60 MB/s U3 128GB97.87064.783
PNY Elite Performance U1 64GB97.86166.725
Lexar Professional 633x U3 256GB97.84268.985
PNY Pro Elite 64GB97.84275.628
PNY Elite microSDXC 128GB97.84230.025
Transcend 600x 32GB97.84239.117
Gobe Magic 104MB/s 32GB97.84288.757
Transcend 95/60 MB/s U3 256GB97.83368.737
PNY Elite Performance U3 256GB97.82454.639
Transcend Ultimate 633x microSD 64GB97.81587.828
Transcend 600x 128GB97.81568.262
PNY Elite-X microSDXC 64GB97.80672.201
Lexar Professional 633x U1 128GB97.80630.847
Sony 95MB/s U3 64GB97.79787.432
PNY Elite-X microSDHC 32GB97.74276.533
Samsung PRO U3 32GB97.73379.849
Samsung PRO Plus 64GB97.73388.257
Transcend 95/85 MB/s U3 32GB97.72488.630
Transcend R95 W85 U3 64GB97.71588.242
Patriot EP Pro 128GB97.70642.439
Samsung PRO Plus 32GB97.66987.571
Samsung PRO U3 64GB97.66078.722
Samsung PRO Select microSDXC 64GB97.66087.740
Samsung PRO Plus microSDXC 64GB97.61588.175
Samsung PRO microSDXC 64GB97.61578.610
Sony 95MB/s U3 32GB97.60687.040
Patriot EP Pro 90MB/s 64GB97.46941.403
Samsung EVO Select microSDXC 64GB97.36125.754
Delkin Elite 633x 32GB97.16280.965
Delkin Black 32GB97.13580.660
Patriot EP Pro 90MB/s 32GB96.96546.992
SanDisk Extreme Plus 90MB/s 32GB96.60772.526
Kingston U3 (90/80) microSD 32GB96.44785.689
Kingston Ultimate 32GB96.00646.126
Lexar Professional 1000x microSD UHS-II 32GB95.92752.137
Panasonic Gold Series 32GB95.27342.837
Samsung PRO Select microSDXC 128GB94.78284.460
Samsung PRO Plus microSDXC 128GB94.77484.345
SanDisk Extreme Plus 90MB/s 64GB94.42472.186
SanDisk Ultra 80MB/s 32GB93.66542.860
SanDisk Extreme 90MB/s microSDXC 64GB90.81741.506
Lexar Professional 633x microSDXC 200GB90.38736.347
SanDisk Ultra 90MB/s microSD 200GB90.24719.216
SanDisk Extreme 90MB/s U3 128GB85.39678.252
SanDisk Ultra 80MB/s 64GB82.53316.022
Lexar Professional 633x microSDXC 128GB82.24122.214
SanDisk Ultra 80MB/s microSD 32GB82.01615.318
Samsung EVO Plus 128GB microSDXC81.38021.763
Samsung EVO Select microSDXC 128GB81.21622.110
Samsung EVO microSDXC 64GB46.64323.383
Samsung EVO microSD 32GB46.47123.988

Compare prices on the SanDisk Extreme Pro SD UHS-II Reader/Writer. The lowest prices are highlighted in the table below.

Card ReaderConnectionModel NumberPrices
AmazonB&H PhotoAdorama
SanDisk Extreme Pro SD UHS-II Reader/WriterUSB 3.0SDDR-399