Synthetic Benchmarks

Various synthetic benchmarks are available to quickly evaluate the performance of direct-attached storage devices. Real-world performance testing often has to be a customized test. We present both varieties in this review, starting with the synthetic benchmarks in this section. Prior to covering those, we have a quick look at our testbed setup and testing methodology.

Testbed Setup and Testing Methodology

Evaluation of DAS units on Windows is done with the testbed outlined in the table below. For devices with a USB 3.1 Gen 2 Type-C interface (such as the Seagate Fast SSD and the SanDisk Extreme Portable SSD that we are considering today), we utilize the Thunderbolt 3 / USB 3.1 Type-C port enabled by the Intel Alpine Ridge controller. It connects to the Z170 PCH via a PCIe 3.0 x4 link.

AnandTech DAS Testbed Configuration
Motherboard GIGABYTE Z170X-UD5 TH ATX
CPU Intel Core i5-6600K
Memory G.Skill Ripjaws 4 F4-2133C15-8GRR
32 GB ( 4x 8GB)
DDR4-2133 @ 15-15-15-35
OS Drive Samsung SM951 MZVPV256 NVMe 256 GB
SATA Devices Corsair Neutron XT SSD 480 GB
Intel SSD 730 Series 480 GB
Add-on Card None
Chassis Cooler Master HAF XB EVO
PSU Cooler Master V750 750 W
OS Windows 10 Pro x64
Thanks to Cooler Master, GIGABYTE, G.Skill and Intel for the build components

The full details of the reasoning behind choosing the above build components can be found here. The list of DAS units used for comparison purposes is provided below.

  • Seagate Fast SSD 1TB
  • SanDisk Extreme Portable SSD 1TB
  • Samsung Portable SSD T1 1TB - No Encryption
  • Samsung Portable SSD T3 2TB
  • Samsung Portable SSD T5 2TB
  • SanDisk Extreme 900 1.92TB
  • WD My Passport SSD 1TB

Synthetic Benchmarks - ATTO and Crystal DiskMark

Seagate and SanDisk both claim read and write speeds of around 540 MBps and 500 MBps respectively, and these are backed up by the ATTO benchmarks provided below. Unfortunately, these access traces are not very common in real-life scenarios.

Drive Performance Benchmarks - ATTO

CrystalDiskMark, despite being a canned benchmark, provides a better estimate of the performance range with a selected set of numbers. As evident from the screenshot below, the performance can dip to as low as 20 MBps for 4K random reads in the Seagate Fast SSD and 25 MBps for the SanDisk Extreme Portable under similar circumstances. The key takeaway is that the Seagate Fast SSD has a slight edge ovr the SanDisk Extreme Portable for low queue depth sequential reads and writes.

Drive Performance Benchmarks - CrystalDiskMark


Introduction and Product Impressions AnandTech DAS Suite and Performance Consistency
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  • Roen - Friday, September 28, 2018 - link

    I wonder how Sandisk gets away with including non-compliant USB adapters for the sake of convenience.

    In the Type-C Specification, Section 2.2, with two sentences at the very end of the section.

    “USB Type-C receptacle to USB legacy adapters are explicitly not defined or allowed. Such adapters would allow many invalid and potentially unsafe cable connections to be constructed by users.”
  • Impulses - Tuesday, October 2, 2018 - link

    They get away because as a regulation body the USB-IF is kinda weak... I guess if SanDisk is using their logos they can fine/sue or call them out, I'll check out the retail box since I ordered one... But yeah that kinda adapter leaves the door open for people to do really stupid things and I doubt it was so much cheaper than just tossing in a Type A to C cable.
  • NCM - Friday, September 28, 2018 - link

    I'm glad the tests addressed thermal considerations. I frequently use external drives to transfer large amounts of data. Sustained writes of a couple of hundred GB cause most SSDs to get pretty hot. I've been known to direct airflow from a compact USB powered fan on to the enclosure.

    It would be good to see enclosure manufacturers pay more attention to providing a decent heat transfer path from the NVRAM chips to the outside world. A simple pad with some thermal paste might work wonders.
  • descendency - Monday, October 1, 2018 - link

    On page 1,

    " It comes with two 18in. cables - a Type-C to Type-C, and a Type-A to Type-A one."

    The picture shows a Type-C to Type-A cable and a Type-C to Type-C.
  • Tams80 - Monday, October 1, 2018 - link

    Definitely Type-C to Type-C.

    Type-A to Type-A were a thing for a while (when USB 3.0 Micro B was the go to, but some companies decided (rightly) that that connector was stupid), so I can understand where the confusion may have occurred.
  • ecthroi - Sunday, October 7, 2018 - link

    the Amazon prices are both at 239.99 right now actually, in case anyone's just seeing this (like me).
  • ravib123 - Sunday, November 11, 2018 - link


    Sandisk doesn’t honor their warranties and has a high failure rate. I had to give up on the warranty and buy intel/samsung/micron who do honor their warranties.

    Lessons learned.

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