Screen dimming

[meridius10]

Not sure about this. I am sometimes getting screen dimming and brightening when I minimise an application and the screen is only showing, it becomes brighter. Is this normal behaviour? I am running my laptop on battery power a lot of the time. I actually noticed this especially when I selected the waterfall landscape background in W7.

I have Intel HD Graphics 4600 and NVIDIA Geoforce 710M graphics drivers. My laptop is the Toshiba Satellite C50-A490. I had to install all the operating system and drivers myself as the laptop is sold with DOS only.

Is there any good free hardware test software that would tell me if I have a GPU, graphics card or other problem? I am certainly hoping and anticipating that this isn't a hardware problem but it would at least put my mind at rest.

Many thanks for any advice.

 

[TrainableMan]

I believe what you are referring to is what Toshiba calls Dynamic Contrast and it happens on purpose.

 

[Fixer1234]

Easy way to tell if it's the battery: plug it into an A/C adapter and see if the problem persists. Laptops are very aggressive about saving power to extend battery time. Also look at the options under power management to see what settings are in place for dimming the screen. If it is an old laptop, the battery or the light that is embedded in the screen could be aging. However, you wouldn't expect those to consistently react to something like minimizing a window; it should affect everything. The symptoms you describe aren't something I would expect to be related to graphics hardware or drivers. They don't know the "meaning" of the screen activity, like minimizing a window; it's all just one big picture.

It could be something like a screen color calibration utility. Photoshop and some other graphics manipulation software come with such utilities (Photoshop's is called Adobe Gamma Loader, and gets auto loaded at startup). It could be that when the computer goes into screen saver mode, that is not calibrated and you could see a brightness difference. If you're talking about just the normal desktop background, pictures do have differences in overall brightness. A picture with deeper or darker colors will make the screen look less bright. How big a difference are you seeing (serious brightness difference, similar to the screen going into low brightness, power saving mode while idle)?

Another possibility: some screens have a live auto-adjustment to optimize the image. See if yours has something like that and try turning it off.

edit: Trainable man is fast. He responded while I was writing. That dynamic contrast was what I was referring to in the previous sentence.

 

[meridius10]

Thanks a lot for the feedback. The difference isn't great but it's noticeable. If it's a software or Toshiba setting I'm not worried, and it may very well be a battery saving issue, but I wouldn't mind doing a comprehensive test of all the hardware anyway. The laptop is new so this is a good opportunity to do it.

Can you recommend any good free software for this?

 

[Fixer1234]

In terms of the screen dimming, just look at things like whether it happens when you are on A/C power, disabling screen dimming in the power management options, and disabling dynamic contrast (just to see if it stops).

Years ago, I used some free diagnostic tools. I'm hesitant to recommend one now because I haven't used any current offerings and can't speak from experience. If you don't get any recommendations from other members, try posting a new thread specifically about that (people with good recommendations might not have found the topic of this thread relevant).

 

[meridius10]

I think there was a difference using AC power but I will need to double check and there are screen dimming options which I will test but probably leave as default. Actually I don't really mind screen dimming but was just concerned about a potential hardware fault.

Nevertheless if I don't get a recommendation here for a diagnostic tool I may post a new thread on this. Toshiba have a PC Diagnostic Tool which inclides 'Display' but I don't think it's particularly comprehensive.

Another issue I have is understanding how to preserve battery life. I tend to run this new laptop down to 10% and then charge. When it gets to 100% I then remove the plug. I am doing this as it's a new laptop and my 10 year old laptop was constantly plugged in and now has a very poor battery life (two new posts needed then?!...).

 

[Fixer1234]

If you want input on battery life, it's probably best to start a new thread.

With older laptops that used NiCad batteries, it was a good idea to do what you are doing to minimize memory effect. If your laptop uses lithium or NiMH batteries, memory effect isn't an issue. BTW, if your 10 year old laptop is still on the original battery, short battery life isn't because of leaving it plugged in. You're doing good if you get 5 years of life from pretty much any kind of battery.

 

[meridius10]

Many thanks for the extra info on battery life. This article also helped me:
http://computer.howstuffworks.com/laptop-battery-overcharged.htm