CARDSPEED - Card Readers and Memory Cards

NEXTO CF OTG

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

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?

• Compact size (77.4x128x24mm³), lightweight (140g including battery, without harddisk), but solid.
• Dot matrix LCD, but small and without backlight or illumination.
• Different fonts: 4 lines of 12 characters for regular operation, 8 lines of 16 characters for browse mode.
• One-button control, the LCD indicates the function for short, long or double press.
• Illuminated border around the button with different segments and colours as status indicator.
• Beep sounds for certain important steps, but not annoying.
• Auto power-off with status review after power-on.

• Mount for 2.5" PATA harddisk, large disks with more than 128GB supported.
• Automatic and on-demand partitioning and formatting available for the harddisk.
• Very fast USB 2.0 storage device.
• Very fast USB 2.0 host for other USB storage devices with FAT filesystem, but limited host power.
• CF Type II slot (not accessible through PC connection).
• Fast transfer with suitable high-speed CF cards or Microdrives.
• No problems powering Microdrives over the CF slot (however less runtime).
• Supports FAT12, FAT16 (including 64kB cluster size / up to 4GB) and FAT32.
• Runs with various CF adapters (not included), but speed will depend a lot on the adapter and the card used.
• Three levels of verify: Filenames/Timestamps only, sample verify (start/middle/end of each file) and full byte-by-byte verify (but extremely slow).
• Browse mode for internal harddisk, CF slot and USB device with copy and delete function for individual folders.

• Built-in Lithium Polymer rechargeable, 3.7V/1550mAh, user replaceable.
• BAT connector for the optional external Lithium-Ion battery pack: 3.7V, 2200mAh.
• DC IN for operation around 5V for the included AC adapter.
• Unit only charges when turned off to prevent overheating.
• Can be charged from USB.
• Soft pouch included.
• Manual in Korean and English, not very chatty, sometimes very brief. USB OTG is a very complex topic!
• The display language is English.

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.

NEXTO CF OTG has...

• No FireWire connectivity.
• 5V DC input, so it comes with a different AC adapter.
• No car charging cable due to 5V DC in.
• A single-cell Li-Ion battery, so you can't use the external battery pack from the NEXTO CF.
• Less CPU power, so copying from the built-in CF slot is slower, especially with small files.

But you should also know that...

• The internal battery lasts much longer.
• It can be fully powered from USB.
• It can be charged from USB.
• The OTG connection with a fast card reader can get faster than the original NEXTO CF, especially with SD 1.1 and MS PRO, but also with fast CF cards.
• You can sync the backup folders from the NEXTO CF to the NEXTO CF OTG at up to 23MB/s.

Optional Accessories

• 17 in 1 CF adapter
• External single-cell Li-Ion battery pack (3.7V, 2200mAh)

Notes on Use

For the moment, just a few notes...

• For powering on, you have to hold the "Copy" button for a few seconds (on popular demand, but I don't like that very much).
• Downloading works with a single press of the "Copy" button from both, internal CF slot or attached card reader with inserted media.
• Multi-slot card readers are supported, NEXTO CF OTG will automatically select the appropriate drive.
• For multi-slot card readers with multiple media inserted, only the contents of the first drive will be copied.
• Limited USB host power, no problem for card readers with flash cards, but card readers with microdrive won't work over the OTG connection (use the built-in CF slot instead).
• High-current USB devices (like external harddisks) have to be powered seperately.
• Whenever external USB host power is applied (through regular USB connection or USB host connection), NEXTO CF OTG assumes PC connection. The usual "Copy" will not be engaged, you have to use the "Browse" function from the menu to access a device that supplies host power (which should not be the case for a proper USB device).
• When using USB Y-cables to power external devices, make sure that the cable seperates data and power lines.
• Erros on the OTG connection are only displayed as error code (error text planned for future firmware upgrades).
• Only FAT filesystems are supported, make sure that the external harddisks are formatted as FAT32.
• PTP devices are currently not supported (planned for future firmware upgrades).
• Sector sizes other than 512 bytes (e.g. 2kB like MD/MO/CD/DVD) are currently not suported (planned for future firmware upgrades).

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

• USB 2.0 PC Connection at 28-30MB/s.
• USB OTG up to 23MB/s (see note below).
• USB 2.0 Card Reader to Harddisk up to 16MB/s (see note below).
• CF Slot to Harddisk up to 13MB/s (see note below).

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 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.

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

Explanations

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.

Files		NEXTO CF		NEXTO CF OTG
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.