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Meet the world’s most efficient high-end desktop computer

Dutch hardware hacker, Emile Nijssen (nickname Mux), claims he has built the world’s most efficient “high-end” desktop computer: An Intel Core i5-3570K with 16GB of RAM, a 64GB SSD, and other assorted bits, that consumes just 5.9 Watts when idling and 74.5 Watts at full load. Your desktop PC, by comparison, likely draws around 30 Watts while idling.

Mux has a bit of a history when it comes to ultra-efficient computers: He built a 50 Watt computer in 2008 (called Dennis), a 20 Watt computer in 2010 (Dennis2), a 9.5 Watt NAS last year (Floppy2), and now the 5.9 Watt Fluffy2.

Fluffy2 is currently just a headless motherboard, but it will eventually be built into an IPS LCD display to create a passively-cooled all-in-one PC that draws less than 20 Watts – the most efficient high-end PC in the world. It’s worth noting that none of these figures include a discrete graphics card, so the term “high-end” could be a bone of contention, but Mux points out that the i5-3570K has an integrated GPU (the Intel HD 4000) that can play most games – at a low resolution with no checkboxes enabled, of course.

So, how does one go about building a 5.9 Watt computer? Well, fortunately Mux is one of those hardware hackers who takes lots of photos, produces his own illustrative diagrams and graphs, and records everything that he does in minute detail.

For starters, Fluffy2 is based on Intel’s DQ77KB mini-ITX motherboard and the Core i5-3570K CPU, which is then paired with two sticks of 8GB DDR3-1333 Crucial RAM, a 64GB MyDigital SSD, an Intel Ultimate-N Wi-Fi card, and a Logitech wireless receiver. In this basic form, mostly thanks to Intel’s 22nm Ivy Bridge architecture, Mux says this is one of the most efficient PC setups possible, drawing just 11.6 Watts when idle. To go from 11.6 to 5.9 Watts – almost exactly half the power consumption – is rather impressive, though.

To do this, Mux does one thing that many of us have tried (undervolting) and one thing that you’ve probably never even considered: Modding the motherboard to be more efficient. Mux begins by analysing the DQ77KB motherboard to discern the flow of power around the board, and the relationship between each of the components, yielding this diagram:

Then, using his well-equipped electronics lab, he works out how much power each component on the motherboard uses, including the all-important conversion losses – the amount of electricity wasted as heat energy when power has to be stepped down from 12V to 5V, 3.3V, and around 1V for the CPU. He turns this data into a proportional diagram, and then a beautiful Sankey diagram, like so:

And here's the Sankey diagram:

With this data in hand, Mux went to work on the motherboard, adding a CPU voltmod, other various voltmods – and then desoldering the PCIe slot, fan header, SATA ports, and an LED, to further reduce power consumption. The end result, if you look pretty closely, is pretty messy – including a few scorched components – but you can’t argue with a 50 per cent reduction in power consumption. While the reduction in idle power consumption is the most important (most home/office PCs are idle 90 per cent of the time), the 25 per cent reduction in max load consumption (99.6 Watts down to 74.5 Watts) is also very significant.

It makes you wonder just how much power (and money) we could save if every computer was as efficient as Mux’s. It’s not like his modifications were particularly complex; Intel and other motherboard makers could easily replicate Fluffy2 and bring such motherboards to the mass market. We are already seeing this at a data centre level, with big web companies such as Google developing their own highly efficient hardware – and of course, when it comes to mobile PCs, reducing power consumption is one of the industry’s prime focuses.

In the future, Mux will post more details about Fluffy2, including detailed guides on how to perform the voltmods yourself, the homebrew UPS (built from a bunch of laptop batteries), and the case for the all-in-one computer (see the video below).