I wouldn't think so. If your card was having issues getting enough power you would probably be getting severely reduced framerates, or system shutdowns if the PSU was struggling to give it enough power, rather than just issues with drawing shadows. To check for a power issue, go into your BIOS and see what your +12V rail on your PSU is giving you. If it is significantly under spec that might cause a power problem. You might want to download GPU-Z and run it in the background to monitor your card's voltage and GPU load. Other than that, I can only suggest you get an exchange for another GT 240 from the manufacturer and hope that solves the problem.