Thinkpads Forum

What's the most power efficient laptop Thinkpad offers?

Mine is an X220 and [url=http://www.amazon.com/gp/product/B005I563OY/]one of these[/url], but I think it's drawing too much power in my "off-grid" setup in an RV, but can't really confirm that, as I don't have an amp meter.

Probably one with an ULV CPU; for example T431s has an ULV CPU which is rated at a TDP of 17W; the CPU of your X220 has a TDP of 35W. Still, X220 has a smaller screen..

I am amazed by the power efficiency of all of the Sandy/Ivy Bridge based models with Intel graphics. Even my T420s with i7-2640m will run on less than 15W with the screen brightness turned to 12, streaming music, and web browsing at the same time. For basic tasks it sips the juice. That is less than my Intel Atom N550 netbook I used to have a few years ago.

Of course LED/LCD display Vs. IPS display can make a big difference. For best power consumption, dedicated graphics and HDDs are out of the question.

The Kill-A-Watt is a good cheap meter that is sold at Home Depot. I use software called Battery Bar Free Basic Edition to get my estimates.

ThinkWiki has a list, but it's not fully up to date http://www.thinkwiki.org/wiki/Idle_consumptions

I think the best combination is a low TDP CPU (many of the older Intel Dual Core low voltage CPUs are 17 W TDP, as opposed to 35 W for many of the standard mobile CPUs) and a newer generation of processor (seems generally that each revision of the Intel Core i5/i7 series has improved idle power slightly, with the most recent Haswell release making a larger improvement), plus an SSD.

TDP does not have anything to do with power consumption. It is a measure of the amount of heat that the cooling system will need to remove from the CPU.

Nevermind, I misread your post the first time through, rjwilmsi. Now I see that you were only suggesting low TDP processors, not that low TDP gives the most efficient consumption.