If you want a quad core development board for less than $100, you only have two choices right now: Radxa Rock powered by Rockchip RK3188, and Hardkernel ODROID-U3 powered by Samsung Exynos 4412 prime. There are also a few Freescale i.MX 6Q boards such as Wandboard Quad and UDOO Quad for around $130 which you could consider because of potentially better software support and features like SATA, but in this post, I’ll compare Radxa Rock and ODROID-U3 to help you decide which one may be right for your application or project.
Let’s get right to the subject, with a side-by-side comparison table.
| Radxa Rock | Hardkernel ODROID-U3 | Comments | |
| Processor | Rockchip RK3188 ARM Cortex-A9 quad core @ 1.6Ghz | Samsung Exynos 4412 Prime quad core Cortex A9 @ 1.7 Ghz | Slight advantage for ODROID-U3, but it’s basically a draw. |
| GPU | ARM Mali-400 MP4 GPU | ARM Mali-400MP4 GPU @ 440MHz | Same GPU, that’s a draw. |
| System Memory | 2GB DDR3 @ 800Mhz | 2GB LP-DDR2 @ 880MHz | Same amount of RAM, but clocked slightly higher on ODROID-U3. Almost a draw. |
| Storage | 8GB Nand Flash, micro-SD SDXC up to 128GB | microSD slot, eMMC module socket | Radxa comes with internal flash, you’ll have to pay $25 extra to get an 8GB eMMC module with ODROID-U3, unless you use a microSD for booting. eMMC performance should be better than standard NAND flash. |
| Video Output | HDMI 1.4, AV Out | micro HDMI | |
| Audio I/O | HDMI, optical S/PDIF, built-in microphone | micro HDMI, 3.5mm audio out jack | |
| Connectivity | 10/100M Ethernet WIFI 150Mbps 802.11b/g/n with external antenna Bluetooth 4.0 |
10/100Mbps Ethernet | WiFi and Bt 4.0 can also be added to ODROID-U3 via USB. Any dongle would do, but they cost $8 each on hardkernel website. |
| USB | 2x USB 2.0 host port, 1x micro USB OTG | 3x USB 2.0 Host ports, 1x USB 2.0 device for ADB/mass storage | |
| Debugging | UART connector for serial console (3.3V) | UART connector for serial console (1.8V) | |
| Expansion headers | 2x 40-pin headers with GPIO, I2C, SPI, Line in, USB 2.0, PWM, ADC, LCD,… etc | 8-pin I/O header | Much more I/O pin available in Radxa Rock,. You can connect a U3-IO shield board ($20) to get more I/O pins and Arduino compatibility on ODROID-U3 |
| Misc | IR sensor, power key, recovery key, reset key, 3 LEDs, RTC | Power switch, power and heartbeat LEDs, connector for RTC back-up battery connector | |
| Dimensions | 100×80 mm | 83×48 mm | |
| Heatsink | No | Yes | |
| Power | 5V/2A recommended | 5V/2A recommended | |
| Enclosure | Transparent plastic case shipped with board | Optional plastic case available for $4 | |
| Android Support | Android 4.2.2 | Android 4.1.2 | Both board should support Android pretty well, although I’m not sure about good I/O control are. |
| Linux Support | Linaro 13.11 Server, and Desktop (Lubuntu) | Xubuntu 13.10 with XBMC | ODROID-U3 is probably the winner here, not because of the distribution supported, but because of GPU and VPU acceleration, and not all I/O may currently be programmable on Radxa Rock. |
| Community | Radxa is very new, so there are not that many people in the community. There’s a form @ https://groups.google.com/forum/#!forum/radxa, and IRC chat #radxa on freenode | Hardkernel ODROID boards have been around for a while and there’s a relatively active community http://forum.odroid.com, and they even have a magazine http://magazine.odroid.com/ | |
| Documentation | There’s a wiki in construction at http://wiki.radxa.com/Rock, tools and OS images are available for download @ http://radxa.com/download/, and source code is available in private git.Schematics are available in PDF format. | Most documentation appears to be in a section of the forums http://forum.odroid.com/viewforum.php?f=50, but there’s also an older, and possibly outdated, wiki @ http://dev.odroid.com/projects/odroid-xq/, as well as Linux and bootloader source code in github.Schematics are available in PDF format. | ODROID-U3 benefits from the work done on ODROID-U2 and appears to currently have more documentation than on Radxa Rock, although it’s not that easy to find… |
| Price | $99 + about $15 to $20 for shipping on Miniand and Aliexpress | $59 (Community edition) or $65 (no limit on order qty) + about $25 shipping | No winner here as there’s more than meets the eye. |
When it comes to raw processing power including CPU, GPU, and RAM, both development boards are equivalent, although ODROID-U3 has a tiny edge, it won’t be noticeable. Radxa Rock comes with 8GB internal flash, whereas ODROID-U3 has none. You can either boot with a microSD card, or purchase an 8GB eMMC module ($25) for optimal I/O performance.
Radxa Rock has more built-in features such as Wi-Fi, Bluetooth, optical S/PDIF, a microphone, and composite output, so if you need any of these, the Rockchip board may be better for you, although you could had external hardware to provide most of these to the ODROID-U3 board.
ODROID-U3 has only 8 I/O accessible via one expansion, although you can augment that with U3-IO Arduino compatible expansion board. Radxa Rock has a clear edge here with two 40-pin headers giving access to a wide range of I/O. Having said that I’m not sure they are all accessible at this stage due to driver issues. GPIO and I2C is working, but I’ve read there may be issues with SPI for example.
I haven’t really tested Android, nor Linux distributions on either device, but Android support should be decent on both devices, simply because both SoC are quite mature. Radxa Rock has a slight edge here because it supports Android 4.2.2 instead of Android 4.1.2 on ODROID-U3, which may really be important if you absolutely need support for some new features introduced in 4.2. You should be able to run all sort of Linux distributions on both board, but ODROID-U3 should probably be better here because of GPU and VPU acceleration support. Of course, if you’re going to use the board as a server, it won’t matter. The Linux kernel is quite old for RK3188 (3.0.x) whereas ODROID-U3 uses a more recent 3.8.x kernel. Support is likely to be better for ODROID-U3, at least for now, simply because Hardkernel ODROID-U(2)((3) boards have been around a longer time, and more people are using them so the community is larger, whereas Radxa Rock is newer, and issues may be more difficult to fix at first.
The total shipped price for Radxa Rock is about $115, whereas ODROID-U3 “community edition” costs $84, so with a $30 price different, ODROID-U3 appears to be the clear winner here. It’s not as simple as that, as you really have to look at your project, and depending on the required features, cost may add-up quite a bit with ODROID-U3. For example, adding the enclosure, 8GB eMMC flash, Bluetooth and Wi-Fi brings the total price to $129 which costs more than Radxa Rock.
Both Radxa Rock and ODROID-U3 have their own strengths and limitations, and as always, you have to select the board that matches your application or project best.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
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