The durons and T-Bird use less power than than the original Athlon but you still need a good PS. Its not true that the reason you need 300w PS for Athlon because the Athlon uses alot of power, its because 300w PS's are usually higher quality than 250w and in those 300w PS they have better regulators or something. That is why you need 300w PS, btw, still many 300w PS dont work with Athlons but its more likely to find a 300w PS than 250w that works with Athlons.