Before you go ahead and update your Samsung Galaxy S5, make sure to leave at least 3GB of free space available. At the same time, you should have the battery on your handset fully charged. Before beginning the updating process, it would behoove you to back up all of the data on your phone.
According to Samsung, apps opened for the first time after the update may be sluggish "due to the initial optimization process required with the Android 5.0 OS." Additionally, some apps installed on your Galaxy S5 might need to be updated from the Google Play Store or Samsung Galaxy App Store in order to be optimized with the latest build of Android. And after the update, the amount of system memory on your Galaxy S5 will decline by at least 950MB.
We have some pictures of the Samsung Galaxy S5 after the Lollipop update. You can take a gander at them by clicking on the slideshow below.
source: Samsung via SoyaCincau