There is only one question to be asked.
Will the following system fit within the 90W (80W in reality) power limit with both cores being thrashed (a worst case scenario if the machine gets infected with a virus).
Antec ISK110 with a 90W power brick but an 80W DC/DC board, according to the printing on the underside of the DC/DC board in the review linked below.
Gigabyte GA-H61N-USB3 - Or Similar.
128GB Samsung 830 SSD.
WD Black 320GB/500GB HDD for backups.
No Optical Drive as there isn't a provision for one in the case.
2x 2GB DDR3 (branded for reliability + warranty purposes) RAM.
Intel Celeron G530 (as its the cheapest) - "T" varieties of 35W CPU's seem to be impossible to buy, meaning that I will end up with a "65W TDP" CPU.
A USB Keyboard and Mouse.http://www.funkykit.com/component/conte ... ml?start=3
Note that the reviewer didn't have any "problems" whilst testing, but they didn't look into this issue with any detail at all, or even test the external power draw and make a DC draw estimate.
This is going to be a server in a small business, I have carefully selected components that are reliable/have good warranties so I wont likely get any grief from failures..... that's where the PSU's "real" power rating comes into it, that's not a component that I can simply swap if it fails, failure would be a real pain in the arse and failure because the DC/DC board or Power Brick are overloaded or close to their maximum load is not something that I would consider.
If its too close for comfort, its going to be a mATX system with a 430W PSU because I wont take the risk with reliability and would rather have a larger system than an unreliable one. And no I don't want to get a horrible puny Atom system that would not save a lot of money (£25) and doesn't even have SATA-3.