XPS 15z: Screen brightness flicker/dim on battery by Intel "Display Power Saving Technology"

When on battery power, the brightness of the Dell XPS 15z LCD screen becomes unstable. If you switch from a bright web page (http://www.google.com) to a darker web page (http://www.nasa.gov), it automatically dim a little. It gets brighter the other way. It's almost like screen flickering when you switch between windows of different brightness.

Apparently this is a feature by Intel to  save power on battery. (Display Power Saving Technology)

"This feature extends battery life by lowering backlight intensity while minimizing impact to display quality. Select Maximum Quality for the best display quality or Maximum Battery to prolong battery life. Clear the check box to disable this option."

To fix it (if you find it annoying), go to Intel Graphics control panel and disable the feature.

Right click on some empty space on Desktop and from the menu choose Graphics Properties > Power > Change the pull down menu on power source from 'Plugged in' to 'On Battery' and uncheck "Display power saving technology". Click OK. Now the flickering should be gone.

I slid the bar to almost left (More towards 'Maximum quality' side) without disabling the feature and it also worked.

XPS 15z: Amazing battery life of 6-7 hrs for general use

I had been monitoring the Dell XPS 15z battery performance for last several days and I can now safely say that I get around 6-7 hours of battery for a normal use for me. By normal everyday use, I mean internet browsing with WiFi always on, chatting with friends, occasionally listening to music using an earbud headset, reading some e-books, writing some reports using Microsoft word, Windows explorer file copy/paste/move operations, browsing files/pictures on the hard disc, installing software here and then, downloading some files, remote connection to Linux work stations/supercomputers over SSH (secure shell) etc. Now if you just want to read an ebook or type in word and only occasional WiFi (disable/enable WiFi using Fn+F2 short key), you may get more than 8 hrs.

Here are some battery monitor logs collected by BatteryMon software from PassMark (http://www.passmark.com/products/batmon.htm)

In the beginning: 7 hrs of battery estimate

After 30 mins: Cloud streaming Google Music songs (http://music.google.com) with Firefox 4 browser for 10 mins drop down the overall battery life estimate to about 6 hrs. i.e, if you wanna stream music all the time, and browse normally you can use the laptop for 6 hrs max.

Returning to normal browsing and now the battery life estimate is back to more than 7hrs (7.5 hours of total estimated time).

 I used windows power saver option with lowest screen brightness(which is still good in a not-so-bright room). Since I do not use bluetooth,  I disabled all the bluetooth associated services.

Control Panel>All Control Panel Items>Administrative Tools>System services

There are four services with bluetooth name and right click on it. Go to properties and stop the service if t is running and change the startup type to 'Disabled'.Click ok. 

Also I disabled a few useless stuffs like Adobe updater, Adobe active file monitor, Dell Datasafe online bacup etc. (WARNING: Be careful in disabling stuffs like that. It may adversely affect your system performance. For example, if you disable Quickset using msconfig, it might result in a defunct DVD eject button.) One thing I must say is that I do not have any clear quantitative estimate of how much battery these services take up. May be some are harmless to battery life even if it is running in the background. Try yourself and find it out.

Now what will drain your battery for sure: 

1) The number one common thing could be playing flash videos while browsing; any news site  like CNN/MSNBC or youtube or all those annoying ads from 100s of sites. My recommendation is use Firefox browser with AdBlock and Flashblock if you happen to visit ad added sites.

2) Dell XPS 15z HD screen is exceptionally bright. I suspect full brightness use when not plugged in would negatively affect not only the battery meter reading but also the overall battery life. So make sure you decrease it. Also may be change default display colors to generic in Mobility center (Windows key + X)

There are many obvious stuffs which will drain your battery like playing video/DVD/running CPU intensive programs (games, video editing etc) etc. But I can assure you, this battery is simply awesome.

UPDATE: If you want to save a little more battery life, you may want to kill two cypress processes (CyCpIo.exe and CyHidWin.exe) through task manager (Ctrl+ Shift + Escape). However, you would lose minor touchpad functionality.

UPDATE: (2nd August 2011) I just found out a side-effect of disabling all the bluetooth services. If you go to Devices and Printers and you don't see any content but windows OS keeps on searching for ever, you have this problem. To fix it go to Control Panel>All Control Panel Items>Administrative Tools>System services and right click on Bluetooth Support Service > Properties  and make Start up type Manual. Then start the service. If you have that Devices and Printers windows open, your all devices will be shown instantly. wow!

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Some interesting Web pages

Browser Face-Off: Battery Life Explored
http://www.anandtech.com/show/2834

Top Tips to Extend Your Laptop Battery Life
http://www.pcmag.com/article2/0,2817,2324229,00.asp

Laptops with the best battery life
http://news.cnet.com/8301-17938_105-20007267-1.html

Dell XPS 15z Multitouch Gestures: User guide

UPDATE: An update for Dell XPS 15z users: Read it if you have some time
XPS 15z: Why you should not buy a premium Dell laptop
http://techienetizen.blogspot.com/2012/02/xps-15z-why-you-should-not-buy-premium.html

This multi-touch trackpad/touchpad feature is new to me and I had to spent some time to figure this out in Dell XPS 15z, fix the problems and get it working well.

Available options from the trackpad are:

a) 2-finger up/down or left/right: Scrolling (vertical and horizontal)

(PS: You have to have the window active and the cursor on top of it to use the feature; i. e if you try to do it for a background window, it won't work. Also if you have a scrollable window inside another scrollable window(eg. Gmail compose window), move the cursor appropriately like the old synaptic touchpad. If you want to scroll the background window, use a free program called WizMouse; http://download.cnet.com/WizMouse/3000-18487_4-10907935.html) It is quite useful for comparing two documents, web pages etc side-by side whicout having to click each window again and again)

b) 2-finger pinch zoom in and out. This was tricky for me. I didn't like it.

c) 3-finger up/down: Switch/change the tab of your browser if you have multiple tabs open, say in firefox. Unlike the above option of 2-finger scrolling, I had to lift my fingers slightly after each 3-finger up/down to get it work. I mean, if I keep fingers in the trackpad and do up then down, it won't go switch between the tabs.

d) 3-finger left/right: Browser/Windows Explorer go backward or forward. Again lift fingers after each left/right.

e) 4-finger up: It's like Alt+Tab, but the window selection panel stays without disappearing so that you can tap (or move cursor) on the trackpad to  select the window you want to change to.

f) 4-finger down: Shows desktop; similar to Windows key+ D

g) 4-finger left/right: Like Windows+Tab key combo. Open 3D window cycle panel with the perspective look. To cycle the windows forward, tap/swipe one(or more) finger keeping the other fingers on trackpad. (If you lift the fingers, the panel disappear zooming up the active window.) Each tap cycles to new window. When your cycle reaches the desired window, lift the four fingers, the window come up and become active for your use. I can't figure out how to cycle backward though; I mean Windows+Shift+tab option.

Now the main problem I faced was this one. When I actually want to scroll with two fingers, sometime it zooms in and out. If you have same problem, may be you can try disabling the zoom options so that you accidently don't zoom when you actually intend to scroll.   If you ever need Zoom options, use keyboard shortcuts (Ctr+, Ctr-, Ctr0)

Control panel> Mouse> CypressTrackpad > Click to Change Cypress Trackpad Settings > 2-Finger Gesters

Uncheck Zoom In/out Rotate boxes

I did this fix and it's working perfect so far.

If you want to enable the old style single finger scrolling, you can do that too.

Hope this might be helpful to someone with the same problem. Please let me know if I'm missing something so that I can learn from you.

UPDATE (June 20th): I was going crazy before I figured this work around but now I'm starting to like this option. There is a small learning curve to master this gestures, but once you get used to it, it'll become very convenient for your everyday browsing (if you use touchpad a lot; not using mouse). May be you need practice for 5-10 minutes. I would suggest you to give it a try.

UPDATE (July 4th):  I updated to the new Cypress trackpad drivers (v 2.3.6.5) and my experience went from awesome to awful. It gave me a frustrating 5-10 minutes of scrolling with jerky movements all the time. So I immediately restored to the old system state with System Restore. May be I'm missing something. I'm not sure whether the trackpad adapts and stores the usage behavior to give better performance? The driver version which I find working well is  2.3.6.3.

UPDATE (Dec 5th 2011):  I accidentally happen to see Dell Reps response to my Dell XPS 15z review on Dell.com. The update is that there is a new driver available for Cypress Trackpad. I copy paste the response here if anyone want to try it out. I'm currently test driving the new drivers and so far it looks interesting. I'll post my feedback on Dell forum soon.

Response from Dell.com:By Bill Bivin, End User Computing Solutions, December 1, 2011

Thank you for the excellent and well considered review. We very much appreciate the feedback. I wanted to provide an update specific to the touch pad drivers. The latest driver reduces the CPU load to peaks of roughly 2% each and a maximum combined average over a 30 minute sample of 1.9% in a normal usage scenario. Please try out the new drivers and post on the Dell Forums if you have any feed back. http://www.dell.com/support/drivers/us/en/usgen1/DriverDetails/DriverFileFormats?DriverId=1GFT0

http://reviews.dell.com/2341_ng/xps-15z/dell-xps-15z-reviews/reviews.htm?reviewID=15509786