Its Not Overheating But..

coolitic

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May 10, 2012
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I have a GTX 560m 1.5 GB VRAM. If I overclock the core to 900 Mhz (but 850 is fine), Occasionally my screen will display artifacts such as warping and random colors moving very fast. Strangely though, my temperatures are just 62-64 Celsius. What's going on? Does this mean I have to increase the voltage?
 

I was hoping that I didn't have to change the voltage...
The reason being that, Afterburner wont let me change the voltage even if I check "Enable Voltage Control/Monitoring" and by turning on unofficial overclocking. Why?