====== DDR Overclocking on XU4 ======

A new higher DDR frequency is now available on XU4 series.\\
Both of Android and Ubuntu supports the frequency set,\\
and only Android provides DRAM governor interface.\\

<WRAP center round important>
  * Android : Available with Android 4.4.4 v4.9 (17 May, 2017) or higher version
  * Ubuntu : Available with Ubuntu (22 May, 2017) or higher version
</WRAP>

===== Android Guide =====
On Android, you can adjust DDR frequency and governor using a new **ODROID Utility**.

=== Governor ===
<code>
# cat /sys/class/devfreq/exynos5-devfreq-mif/available_governors
simple_exynos   performance
</code>

=== Frequency ===
<code>
# cat /sys/class/devfreq/exynos5-devfreq-mif/available_frequencies
165000  206000  275000  413000  543000  633000  728000  825000  933000
</code>

ODROID Utility has been updated with the new release version.\\
You can change devfreq governor and frequency using it.\\

{{:en:screenshot_2017-05-17-05-27-49.png?nolink&800|}}

===== Ubuntu Guide =====

On kernel 4.9, you can change ddr frequency using boot.ini interface.\\
The available frequency set is **933MHz, 825MHz, 728MHz and 633MHz**\\
and the default one is **825MHz**.\\
As we check the benchmark score using **mbw**, about 10% improvement can be expected.
=== boot.ini ===
Please find **ddr_freq** in boot.ini and change the value.
<code>
...
# DRAM Frequency
# Sets the LPDDR3 memory frequency
# Supported values: 933 825 728 633 (MHZ)
setenv ddr_freq 825
...
# set DDR frequency
dmc ${ddr_freq}
...
</code>
And then please make sure to reboot the system.
<code>
# sudo reboot
</code>


===== AnTuTu Benchmark Score =====

Here is a AnTuTu benchmark score.\\
We checked the following two cases.\\
  * Case 1 : cpu governor - performance / devfreq governor - performance / devfreq clock - 825MHz
  * Case 2 : cpu governor - performance / devfreq governor - performance / devfreq clock - 933MHz

{{:en:xu4_antutu_totalscore.png?700}} \\
{{:en:xu4_antutu_details.png?700}}

^     ^  Total  ^  3D  ^  UX  ^   RAM  ^
|  825MHz  |  52741    |   11081  |  12770   |   5758  |
|  933MHz    |  53753    |   11249   |  13051  |  6207  |