What's the difference between standard 250Watt
and high performance 300-550 Watt power supplies?

A High-end power supply is quiet, more reliable, and has better cooling mechanism with more power connectors. The main advantage of a high-end power supply is that it produces continuous voltage to minimize computer crashes, even if you run multiple applications simultaneously. Many computer crashes have something to do with the power supply, which most users do not know. When running multiple 3D games or applications, your computer needs a good power supply to be stable. That's why many high-end workstations use high-end power supplies. ATXCASES has tested all brands we carry and all meet today's users needs for high-end quality. ATXCASES carry's 250Watt - 550Watt power supplies. ATXCASES has chosen the high-end manufactories with great rating to eliminate client's problems down the road with cheap." High Watt, but low quality power supplies most others sell".