ITProPortal's resident overclocker has been working with a product you might not initially expect a die hard overclocker to be interested in: the Raspberry Pi.
For a while now, the Pi has been a topic of interest on overclocking site Hwbot.org and we were curious to see what this tiny, super cheap computer is capable of when combined with both extreme cooling and an extreme volt mod.
Joost connected the Raspberry Pi to a EVGA EPower module, more commonly used by overclockers to deliver extra current to a graphics card. Fun fact: the EPower is about three times as large as the Raspberry Pi proper (and costs about three times as much, too).
Thanks to the EPower we were able to increase the voltage of the Broadcom SoC on the Pi significantly. By default you can raise the Pi's voltage to 1.4 Volt (the standard voltage is 1.25V), but the EPower enabled us to go much higher. In order to reach the maximum possible overclock, we used about 1.8 Volt.
In addition, Joost used a phase change cooler to lower the Pi's temperature to about minus 25 degrees Celsius. In order to do this, the Pi was isolated using plastic spray and outfitted with a custom heatsink.
For now, it appears further overclocking is limited by the software or firmware of the Raspberry Pi: as soon as we raise the clock frequency over 1.5 GHz, the operating system refuses to start. Even so this is a pretty extreme overclock, as the default frequency of the Pi is 700 MHz.
To gauge the performance increase, we used the Java based HWBOT HWBOT Prime benchmark, which completed with a score of 795.18 pps, a world record. Interestingly, this performance approaches that of Intel's slowest Atom processors.
You can read the rest of the Raspberry Pi overclocking test at Hardware.info.