  High performance computing (HPC) devices is no longer exclusive for academic,
R&D, or military purposes. The use of HPC device such as supercomputer now
growing rapidly as some new area arise such as big data, and computer
simulation. It makes the use of supercomputer more inclusive. Todays
supercomputer has a huge computing power, but requires an enormous amount of
energy to operate. In contrast a single board computer (SBC) such as Raspberry
Pi has minimum computing power, but require a small amount of energy to
operate, and as a bonus it is small and cheap. This paper covers the result of
utilizing many Raspberry Pi 2 SBCs, a quad-core Cortex A7 900 MHz, as a cluster
to compensate its computing power. The high performance linpack (HPL) is used
to benchmark the computing power, and a power meter with resolution 10mV / 10mA
is used to measure the power consumption. The experiment shows that the
increase of number of cores in every SBC member in a cluster is not giving
significant increase in computing power. This experiment give a recommendation
that 4 nodes is a maximum number of nodes for SBC cluster based on the
characteristic of computing performance and power consumption.
