T400 power consumption statistics

I have a T400 with P8600, CCFL WXGA+ screen, switchable graphics, 6 cell battery, 4 GB ram, and upgraded Seagate 7200.3 320 GB hard drive. I am running with Intel 5300 wireless card.

I was hoping to gather some power usage statistics in a single thread to see how power efficient the T400 can be.

I made the following observations and noted the following power consumption figures while on battery for power manager and running integrated graphics:
8 watts flat at lowest brightness, wireless off, optical drive off; system is completely idle with some applications running (applications that don't access hard drive or strain CPU should have negligible impact)
Turning on wireless costs about 1 watt of power consumption.
Having the optical drive turn off automatically or disconnecting it manually via "safely remove hardware" does help to save power. I think I dropped about a watt even though I had no media in the drive.
At a reasonable half brightness, wireless on, and reading a webpage, power consumption at its lowest was about 10 watts. Actively browsing would raise power consumption and it would hover around 12-13 when actually loading webpages.

Based on Tom' Hardware, my hard drive is one of the more efficient 7200 rpm ones, sometimes even beating 5400 rpm models. I know though, that I am still making a small battery life sacrifice for performance. What I do wonder though is how much more power am I using because I had to buy a CCFL screen instead of LED for the WXGA+ resolution.

I haven't had to run the battery on a full 100% charge yet but I estimate that a full charge usage with wireless on would give me nearly 5 hours but I'm not sure.

Anyone else willing to share some figures?

 

Hmm...makes me wonder if something is up with my system. My setup should be getting lower power numbers with the slower processor and LED screen (spec in sig). I wonder if my WD Black 7200 RPM drive is the main culprit. I am using the default installation and I uninstalled everything lenovo related sans power manager, fingerprint reader, and active protection.

 

Well P8600 drops to 800 MHz so if your processor does the same then the heat output would be the same. If not, the difference should still be small.

I am also running the default installation and I have kept most of the thinkvantage stuff. I uninstalled the lenovo connections manager though. I think it's just a matter of making sure you have no processes that cause hard drive access or too much CPU usage.

I notice that it's very inefficient with 4GB of ram to hibernate the computer most of the time. It's because not only does it take a long time to store what's in memory, after you resume, windows spends time accessing the hard drive to refill the memory cache for superfetch.

 

hello, how to check the power consumption ?

 

Lenovo's Power Manager utility on the last tab, Battery Info it shows you the wattage used by your T400 when running on battery.

 

Yea, this is a bit of a shame, but even with 4GB RAM I still use it—because it’s still MUCH faster to come out of hibernation with 12 apps ready to do your bidding than it is to boot and then open 12 apps. Moreover, Windows does its SuperFetch dance whether coming out of hibernation or booting so you pay the piper regardless. Now when 4GB notebook DDR3s come down in price, and I move to 8GB RAM, hibernation will likely be a good deal more painful.

FWIW, on a clean install of Windows 7 RC, plus a few beta Lenovo utilities, 60 percent brightness AND using the ATI card, I do between 12 and 13 watts under very light usage. I imagine this will improve when 7 goes gold and the drivers and related software are up to speed for this OS.

 

Try using rmclock undervolting using superlfm mode. It cuts the FSB by 50%, so components like northbridge use less power. Would be interested to know if you get better results using it.

 

Yeah I should have said that Sleep might use less battery than hibernate for short periods and there's barely any time to wait before the computer is usable.

I'm not going to try to undervolt my computer right now. I'd rather conserve power with good usage habits and power plan settings than spend too much time for a watt of savings.