Black Screening under load

Hello,

So I recently decided to go out and build my first computer. Everything has been going fine and it is working well. However a problem has surfaced, when my GPU, MSI Radeon HD 7970, hits around 60 degrees celsius it will black screen. The sound will continue most of the time, sometimes it won't though. I usually will have to do a hard restart to be able to see anything again. Then when the computer start booting the windows logo will have graphics problems, there will be little lines on the screen where colors are. This will continue on to the login screen. Although, if I let my computer rest for around 10 minutes the lines will not be there on start up. I have tested this on a couple stress testers to see just exactly what happens and it does seem to be related to the temperature of the GPU. Would love some experience insight.

Best Regards,
Tanner