Aporte original por: Dan ,
When your display goes in to magenta mode plug in an external display and see if the external has the same magenta coloring. If it does then the display and display cable are not the problem. Most likely the GPU is the problem. Given the fact you have an over heating system I would do a thorough cleaning of the fans & heat sink fins of any dust buildup. If you don't have than much dust buildup I would clean off and redo the thermal paste on both the CPU & GPU's make sure to use a good quality paste. Did you replace your HD? If you did you may want to check the EFI firmware and also check the SATA I/O data rate of the new drive. You may have a problem your system has a SATA II (3 Gb/s) interface and your drive maybe SATA III (6 Gb/s). What happens is the I/O fails to read or write causing the CPU to work harder which then over heats your system.