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DyDx
Paper Tape
Posts: 3
Registered: ‎12-01-2009
Location: Massachusetts
Views: 1,882
Message 1 of 12

Higher-than-expected power draw, T400s

Is anyone here using a T400s with a spindle HD? 

 

I'm getting something like 40-50% less battery life than that reported by laptop reviewers, such as those at laptopmag and notebookreviews.com.

 

The review on notebookreviews.com notes that during their battery test (70% screen brightness and wireless ON), the power draw was 6.5-8W depending on the activity and they got nearly 6 hours of battery life. However, with my T400s, if I use the 'Basic' power settings and put the meter all the way to the right, the minimum power draw I see is 13 or 14W. This perfectly matches the <3 hours of battery time I am seeing considering the battery has a max charge capacity of ~44Whr. 

 

So clearly something is causes more power to be drawn than it necessarily should.

 

The reviewers were using SSD drives, which DO draw less power -- however, a cursory glance at some specs online show that the difference is small: 

 

Intel 80gb 1.8" SSD, idle: 0.06W, read/write: 1.5W
WD 320gb 2.5" 5400rpm SATA: idle: 0.8W, read/write: 2.5W

 

I've also heard that Windows 7 tends to keep the spindle spinning all the time, but even 2.5W versus 0.06W is a much smaller difference in wattage than the comparison between my power draw and what reviewers saw. 

 

I am pretty sure all my software is up to date, but I'll double check.

 

Does anyone have any ideas or are my experiences typical?

wesleyyin
802.11n
Posts: 236
Registered: ‎07-02-2009
Location: US
Views: 1,868
Message 2 of 12

Re: Higher-than-expected power draw, T400s

Recommend:

 

Run cmd.exe with administrative priviledge, then run "powercfg - energy".

 

DyDx
Paper Tape
Posts: 3
Registered: ‎12-01-2009
Location: Massachusetts
Views: 1,827
Message 3 of 12

Re: Higher-than-expected power draw, T400s

That is somewhat useful. However, it turns out that the ThinkVantage software was NOT set to automatically update [strange...] and upon updating I saw the power draw drop 3-4 watts, which is a nice improvement.

 

It's still not great, but it's better.

wesleyyin
802.11n
Posts: 236
Registered: ‎07-02-2009
Location: US
Views: 1,821
Message 4 of 12

Re: Higher-than-expected power draw, T400s

 


@DyDx wrote:

That is somewhat useful. However, it turns out that the ThinkVantage software was NOT set to automatically update [strange...] and upon updating I saw the power draw drop 3-4 watts, which is a nice improvement.

 

It's still not great, but it's better.


 

I am curious to know how you get the watts? I run powercfg -energy on my T400s and saw a bunch of USB hosts/hubs/devices that cannot go to sleep.

 

DyDx
Paper Tape
Posts: 3
Registered: ‎12-01-2009
Location: Massachusetts
Views: 1,742
Message 5 of 12

Re: Higher-than-expected power draw, T400s

The ThinkVantage Power Manager tells you the power use in watts if you are in 'Basic' mode.

wesleyyin
802.11n
Posts: 236
Registered: ‎07-02-2009
Location: US
Views: 1,721
Message 6 of 12

Re: Higher-than-expected power draw, T400s


@DyDx wrote:

The ThinkVantage Power Manager tells you the power use in watts if you are in 'Basic' mode.


 

Thanks!

TheDude
802.11n
Posts: 541
Registered: ‎09-10-2009
Location: USA
Views: 1,664
Message 7 of 12

Re: Higher-than-expected power draw, T400s

Funny,

Mine is using 6357 watts. The computer should melt.

T61p, T400
formerly x23, x40
damonlynch
Token Ring
Posts: 71
Registered: ‎12-08-2009
Location: US
Views: 1,602
Message 8 of 12

Re: Higher-than-expected power draw, T400ss

The SSD achieves idle state much more quickly than the hard drive, so it spends more time in idle. That probably has  a lot to do with it.

houtsma
HDMI
Posts: 150
Registered: ‎10-21-2009
Location: Netherlands, Hilversum
Views: 1,565
Message 9 of 12

Re: Higher-than-expected power draw, T400ss

Mine is between 10-22  Watts average. Most times around 10-13. But like now constantly on 22. I have no idea what is causing it to be so high (22) at this moment. Maybe scanner is running in the background or Windows Update or some other process... Oh well.

 

Update: ok, it was Windows Update indeed. Now (after a reboot), it's back at 10 Watts.

 

 

--

jan

--- Lenovo Thinkpad t440p (20AN-CT01WW) + SAMSUNG MZ7TD512HAGM-000L1 SSD + 16G SDRAM + 14.0FHD 1920x1080 ---
Highlighted
T400Plus
Ctrl-Alt-Del
Posts: 43
Registered: ‎01-06-2009
Location: Mumbai,India,PLanet Earth, ON Top U.S.A.
Views: 1,506
Message 10 of 12

Re: Higher-than-expected power draw, T400ss

I have a vintage T400.(i.e. p8400 with 2 1GB DDR3 memory chips).Whic version of the power manager (windows XP sp3) provides the wattage display.I have got the latest updates via thinkvintage.

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