The first, and less severe, Power Saving Mode option limits maximum CPU performance; reduces display brightness and frame rate; turns off the backlit buttons next to the GS6 home key; disables vibration feedback; and minimizes the amount of time the screen is lit when you're not using it.
Ultra Power Saving Mode takes it a bit further. For example, it applies a grayscale theme to your device, so it uses no bright colors; it limits the number of available apps to preset "essentials" and any others that you deem necessary; turns off mobile data when the screen is dark; disables Wi-Fi and Bluetooth.
You can check the GS6 Battery page for estimates on just much life is left on your device in normal mode, Power Saving Mode and Ultra Power Saving mode, to help plan when to switch between them. The iPhone 6 has a number of software-based battery optimization tweaks, and you can check battery usage states, but it has nothing like either of the two GS6 power saving modes.
6) Samsung Galaxy S6 'selfie cam'
From a selfie perspective, the GS6 owns the iPhone. Not only does it have a higher-resolution camera (5MP) than the iPhone (1.2MP), it takes noticeably better selfies in a variety of lighting conditions. (Why, yes, I did take selfies all over Boston during the past week to test the cameras.)
al sacco selfieSacco selfie taken with Galaxy S6.
My favorite thing about the GS6 selfie cam is the capability to the tap the flash panel on the rear side of the device to take a picture with the front-facing shooter, instead of having to awkwardly tap the display with your thumb and possibly shake the device at that crucial moment when your selfie is just perfect.
Honestly, I can't remember the last time I took a selfie before I got the GS6. I am, however, aware that society at large holds selfies in high regard these days, for better or for worse, so the GS6's selfie dominance over the iPhone seems relevant.
Again, this article tells only one side of the story, so be sure to check out my companion piece, "4 things iPhone 6 does that Galaxy S6 can't."
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