[Dougie Fresh]

Does anyone have any real-world experience of the power drain on an i3 or higher? Are they genuinely as low-power as is rumoured?

Yes, I've measured a lot of PC's power consumption. What I've found with Intel Sandy/Ivy Bridge is across the line idle power consumption is about the same whether it's a Celeron or i5. Even with simple HTPC tasks like watching 1080p video, they are very close. It's only at load where the power consumption profile changes with the more powerful processors using more power as you would suspect. That makes them very good server processors. Don't forget about the LGA1155 Xeon processors too if you're looking high-end.

[snoopy86]

If you'll be running the tasks you have mentioned in your first post, cpu won't get to 50% on i3. Power consumption shouldn't get past 50W.

[Prof Yaffle]

Next you'll be asking when Amazon has their 100% off sale.

You mean you missed it? :-))

Powerconsumption while idle is about ~30W, max power if encoding 1080p material never goes higher than ~55W, the box stays cool and quite quiet (?!).

Yes, I've measured a lot of PC's power consumption...

Excellent, thanks, guys - that's what I was hoping to find out, so a Core (or Xeon) is perfectly suited to this without melting the planet on its own. All I need to do now is convince myself of the overall architecture (to RAID or not to RAID, whether it makes sense to put tvheadend on the same server because of the inevitable firmware challenges on a NAS-alike OS).

Many thanks for the thoughts and suggestions.

EDIT - adding Snoopy86 to that last thank you as well!