The answer is yes but this still belongs in the VGA forum as it's 75% VGA and 25% PSU inquiry. Not to mention you're more likely to run into people that know power draw of video cards in the VGA forum than here.
Considering a roughly state of the ART pc barely draws 500w I think your mid - high end PC would be somewhere in the 250 - 300w range. Including a GTX 275 or HD 4890.