I am a home school teacher, and run my SP3 (i3) ALL day long. At least 12 hours a day, sometimes a little longer, but sometimes less. It never sleeps, the screensaver just pops up, and I occasionally turn it off for a little while here and there. So, used for school and personal use. My SP3 specs: Intel Core 1.50GHz (i3) 4GB RAM 64 bit OS x 64 based processor Win 8.1 Pro My SP3 is used mostly for web browsing and video/music, One Note, and some apps, no gaming of any kind. I have felt it get warm in the upper right hand corner, but only hot if I'm doing a Netflix marathon. I know the i7 can have overheating issues, but am still concerned about my i3. I'm concerned about over working my new SP3. This is an expensive computer, but I do have the 2 year Microsoft warranty. I have an appointment this Saturday because the pen has already stopped working. (the purple top click part) It still writes on One Note just fine, though. I also want to consult with them about the printer issue. (I posted that in a different thread) I've been reading around the forums, and read the "yellow line" thread, and glad to say I don't know what that is, but hope that the pen issue isn't a sign of more negative issues to come, possibly due to my usage. I've only owned this SP3 about a month, and the pen has already stopped working. That really disappoints me, but I do still really love my SP3. Am I over doing it/hurting it by using it so many hours a day?