If i use AMD overdrive on my ATI Radeon HD 5670?

Nobody can tell your for sure man, all cards aren't created equally. It's all trial and error. Start with core clock and get the highest core clock you can before seeing artifacts( black dots and graphical errors) test with furmark for stability. Then once you've got your core clock set it back to default and find the highest shader clock, and then once done, put them both to their new frequencies and test for stability

must be getting too warm. a touch basic yet useful try is to do away with the factor panel of the laptop case and go away it off - assuming the case is someplace open so as that air can bypass. If the photos carry close stops or occurs a procedures much less frequently then that's overheating. If this fixes it then go away the case factor off completely (distinctive human beings do) or in good shape extra cooling followers to the case.

a safe clock to set it to is 3000