Yeah, I'm sure. Dell uses good power supplies and rates them for continuous usage rather than peak like a lot of other brands.
The max TDP of the Q8200 is 95w while both of the cards we are discussing use less than 60w of power. The rest of your system likely draws less than 50w max. A few times on here people have reported using HD5750s on 300w Dell PSUs even.
Is it safe to test these cards on PSU? as in any risks in case I have a cruddy PSU? also can the 512mb do 1080p well?