In win H-Frame SFF Build Mini-ITX i3 750Ti Media/Gaming PC

[Valantar]

Thanks for that.

Yes, the PSU is of a very high quality from what I've found out (Japanese made).

Indeed that is true. My SFF setup is very frugal because of the M-itx and the open air setup which requires no case fans, and a single SSD which uses very little. Nonetheless, it would be good to try undervolting since I have the option available through my motherboard and therefore keeping the power draw close to the mark where its at its most efficient.

Sounds like a good idea. It's also worth noting that Kitguru doesn't say where or how they measured their power draw, but it's likely at the wall for whole-system power, meaning the 159W number includes PSU losses. The PSU in their unit hits its 85% peak efficiency at around this load, which means the internal draw is no higher than 135W - and that's the number you need to watch, as PSUs are rated for output, not input power. With undervolting you'll likely get down around the 110W mark for internal draw, which is just above 60% of your PSU's rating.