[Newbie here, just made an account to find help after Samsung expected me to pay 300$ to repair a 200$ tablet]
My tablet has been restarting itself and shutting itself down out of nowhere. Im stuck at the homescreen, as soon as I slide to unlock the tablet, it shows these weird lines across the screen and reboots itself in an endless loop. The only way I can get past the unlock screen is by connecting the tablet to a power source or to my computer, which halts the problem until I disconnect it again.
I tried my best to figure out what the problem was, and I reached the conclusion that its a GPU/CPU problem.
When I activate the power saving mode on my tablet (Samsung Galaxy S [SM-T700]), the problem subdues dramatically (only the artifact lines show occasionally) and the random rebooting stops.
The power saving mode bottlenecks the CPU performance to reduce battery usage, which might be the reason the issue subdues. However, as soon as I deactivate the power saving mode, the tablet immediately crashes and reboots itself and the problem repeats.
I have tried a soft reset, a hard reset, and a whole factory reset, as requested by Samsung support) and it does nothing. In fact, the tablet crashed right after I got through the Welcome page.
Ive had this tablet for about three months and it has worked fine until recently. I do have to say I use it alot, however.