CARDSPEED - Card Readers and Memory Cards


V0.85 - Notes on Firmware and Successor, First New Test Results

For comparison with other NEXTODI models, see the  NEXTO Product Family Overview .

The original NEXTO CF OTG ND-2300 is now replaced by the NEXTO CF OTG Xpress ND-2300. The main difference between the two versions is an improved power management and a backlit LCD for the OTG Xpress. The software features of the OTG Xpress are available for the original model with firmware update 1.22 or higher. If you are running Firmware 1.20 or 1.21, you should upgrade to version 1.22 to regain support for CF larger than 8GB.

The new firmware offers a significant increase in backup speed.

Built-In CF Slot

Brand Type Test
From Time Speed
Transcend CF 266× 8GB 192×5MB 960MB CF 74.34s 12.91MB/s
SanDisk CF Extreme IV 4GB 192×5MB 960MB CF 74.71s 12.84MB/s
SanDisk CF Extreme III 16GB 192×5MB 960MB CF 77.73s 12.35MB/s
Transcend CF 120x 8GB 192×5MB 960MB CF 74.39s 12.90MB/s
SanDisk CF Ultra II 2GB 192×5MB 960MB CF 92.16s 10.41MB/s

The other test results will be updated later...

Important Note: NEXTO CF OTG was intended to be released in Korea first as "field test". It looks like some of this first batch "leaked" to other markets. The "international" batch is supposed to be delivered with Firmware 1.03. If you have a device with Firmware less than 1.02, you are using it at your own risk! All test results below were taken using Firmware 1.03.

Table of Contents

What is NEXTO CF OTG ND-2300?
Important Notes for NEXTO CF ND-2500 Owners!
Optional Accessories
Notes on Use
Test Results Overview
Detailed Test Results


What is NEXTO CF OTG ND-2300?

NEXTO CF OTG Connectors
  BAT    External battery, single-cell Li-Ion or Li-Poly battery.
  PC    USB 2.0 connection to PC
  OTG    USB 2.0 OTG host connection
  -    Reset button
  DC IN    5V AC adapter

Important Notes for NEXTO CF ND-2500 Owners!

If you already own the NEXTO CF and consider getting the NEXTO CF OTG as well, there are a few things that you should know. If you do not own the NEXTO CF, you can skip this section.


But you should also know that...

Optional Accessories

Notes on Use

For the moment, just a few notes...

NEXTO CF OTG and Card Reader Sticks
Although the use of CF adapters might be more convenient for downloading non-CF media, the fastest solution is using appropriate card reader sticks. The picture above shows the "Hama TravelDrive Mobile 1000&1" that will read SD/miniSD/MMCplus/MMCmobile, microSD/MMCmicro and MS/MS PRO/MS Duo/MS PRO Duo without the need for any card adapters.

Test Results Overview

Note: The copy performance for operations controlled by the NEXTO CF OTG depends a lot on the file size and the number of files per directory. The NEXTO CF OTG has best performance with large files up to 1GB and a small number of files per directory. However, the performance with about 300 files of 1MB, for example, is still very good compared to other OTG devices.

Detailed Test Results

USB 2.0 Harddisk Performance

This is the graph showing the transfer rate of the Hitachi Travelstar 7K100-100 HTS721010G9AT00 inside the NEXTO CF OTG over USB 2.0 connection. The blue and green line show the performance of the harddisk itself, while the purple line shows the performance of the harddisk over the USB 2.0 connection of the NEXTO CF OTG.

USB 2.0 PC connection with Hitachi 7K100-100 HTS721010

USB OTG performance from Harddisk to Harddisk

The USB OTG interface connecting to other USB harddisks runs at UDMA-2 speed with a peak performance of about 28.5MB/s. Transfering 16 files of 1GB each from the NEXTO CF to the NEXTO CF OTG takes 11m42s giving a transfer rate of 23.3MB/s. Transfering 8 folders, each holding 640 files of 3MB (15GB total) takes 28m21s giving a transfer rate of 9.0MB/s. The performance drop is due to the 640 files per directory, but the scenario equals 8 downloads from a 2GB card filled with 8MP images and is absoluetely realistic.

The tables show the results from NEXTO CF OTG "sync" operations copying data from the NEXTO CF with HTS541080 harddisk to the NEXTO CF OTG with HTS721010 harddisk. Copying files and folders to or from USB harddisks shows very much the same performance.

Maximum and real-world performance of the USB OTG interface.

Folders Files Size Total Time Transfer
1 1 4095MB 3.999GB 2:57.38 23.08MB/s
1 16 1024MB 16GB 11:42.05 23.33MB/s
8 640 3MB 15GB 28:21.25 9.02MB/s

File count and files per directory impact.

Folders Files Size Total Time Transfer
1 1 1024MB 1GB 0:45.92 22.29MB/s
1 128 8MB 1GB 0:55.18 18.55MB/s
1 256 4MB 1GB 1:10.38 14.54MB/s
1 512 2MB 1GB 2:01.10 8.45MB/s
1 1024 1MB 1GB 5:11.70 3.28MB/s
4 256 1MB 1GB 2:10.35 7.85MB/s

These results show the strong impact of the file count, especially the number of files per directory.

Copy Performance with USB 2.0 Card Readers

The best performance was achieved with a card reader using a Genesys Logic GL819 controller and the Transcend 150x SD card. Copying a single file of 960MB takes 58.35s giving a transfer rate of 16.45MB/s. Copying 320 files of 3MB each takes 94.37s giving a transfer rate of 10.17MB/s.

Copying 960MB from a GL819 card reader to the HTS721010 harddisk.

  320×3MB 120×8MB 1×960MB
Card Time Transfer Time Transfer Time Transfer
Transcend 120× CF 1:36.39 9.95MB/s 1:08.36 14.04MB/s 1:00.53 15.85MB/s
Transcend 80× CF 2:14.26 7.15MB/s 1:45.71 9.08MB/s 1:37.33 9.86MB/s
SanDisk Ultra II CF 1:36.10 9.98MB/s 1:38.34 9.76MB/s 1:30.69 10.58MB/s
Transcend 150× SD 1:34.37 10.17MB/s 1:05.92 14.56MB/s 0:58.35 16.45MB/s
Panasonic Pro High Speed SD 1:43.59 9.26MB/s 1:13.97 12.97MB/s 1:06.42 14.45MB/s
SONY MS PRO Duo 2:20.03 6.85MB/s 1:51.35 8.62MB/s 1:44.10 9.22MB/s

Copy Performance from the built-in CF Slot

The built-in CF slot runs at PIO-4 speed with a peak performance of about 14.6MB/s. Copying a single file of 960MB from a Transcend 120x CF takes 73.60s giving a trasfer rate of 13.04MB/s. Copying 320 files of 3MB each takes 109.50s giving a transfer rate of 8.76MB/s.

Copying 960MB from the built-in CF slot to the HTS721010 harddisk.

  320×3MB 120×8MB 1×960MB
Card Time Transfer Time Transfer Time Transfer
Transcend 120× CF 1:49.50  8.76MB/s 1:20.91 11.86MB/s 1:13.60 13.04MB/s
Transcend 80× CF 2:12.55 7.24MB/s 1:43.44 9.28MB/s 1:34.84 10.12MB/s
SanDisk Ultra II CF 2:07.57 7.52MB/s 1:38.10 9.78MB/s 1:31.15 10.53MB/s


The NEXTO CF OTG uses the same procedures as the NEXTO CF. However, the NEXTO CF has a different CPU with about 10x the processing speed of the USB OTG chip. The main problem for the NEXTO CF OTG is a large amount of files in the same directory. Performace is OK for about 300-400 files per directory, but then processing becomes slower and slower and slower. There are efforts to improve the file handling procedures, so there is hope that this issue will be solved with a new firmware.

Comparison between NEXTO CF and NEXTO CF OTG: Copy from the CF slot with large file count. Card: 8GB Transcend 120x CF.

Count/Size Total Data Time Transfer Time Transfer
640×3MB 1920MB 2:58.17 10.77MB/s 4:26.97 7.19MB/s
1280×3MB 3840MB 6:18.51 10.14MB/s 12:03.94 5.30MB/s
2560×3MB 7680MB 14:19.10 8.93MB/s 37:17.36  3.43MB/s

Important note: The NEXTO CF OTG CPU has no impact on file transfers from the OTG unit to PC. This is only affected by the PC's CPU, the OS and the harddisks used.


Hans-Jürgen Reggel   ·   ·   2006-05-04 ~ 2007-06-11