I won't disagree that measurement devices are not always accurate. But even a 50% error could not get you 5W from a 20-25W load. My tester is fairly cheap, but it is within 1W on known loads and matches what the serve the home review said about the board.HFat wrote:Let's not rush to conclusions. Some cheap measurement devices are especially bad at charaterizing small loads.
I started in the same boat as you, but at least over here there were non-Atom options. There were a few boards with low power Celerons in the same price range. I have a board with a Celeron 1037U and despite its 17W TDP it uses exactly the same power as my D510 at idle. Paid the same as well, about $100 CAD. There were Celeron 847 boards before those.Like many, I've been using mobile Atoms for light server duty because they were offered as part of affordable and efficient boards. That hasn't been the case for non-Atom Intels in a long while. Again, other conditions are rarely similar.
I just checked and I could still get new Celeron 1037U boards, but the seem to being phased out for the Bay Trail boards. Not necessarily a bad thing, but it was nice to have the option of higher performance in the same price and form factor.
I would say it is a combination of both. People have actually measured the load on the 12V CPU line on Haswells and seen how low they go. That is why there was the worry about "Haswell compatible" PSUs being needed.The reason you can get efficient Haswell systems now is not that the CPU idles at less power than the oldest "Core" CPUs but that the other parts included in typical systems have become more efficient.
Core and the original Atoms had the disadvantage of needing at least two major support chips, while the i series and D series Atoms only need the PCH or what was called the southbridge.
Part of the problem is finding power use numbers for Haswell systems that are not using crazy PSUs that are way out of their efficiency range. I tested a Haswell Pentium system with a DC-DC board and got 37W while running both prime95 and furmark at the same time, plus the system had a 3.5 drive. I was only testing to see if the 60W brick could cope with the system so I didn't write down the idle and I don't have convenient access to that system anymore.