The Rosewill CAPSTONE-550 power supply has a maximum wattage output of 550W. This is a mid-range capacity, and should be fine as long as it is part of an equally mid-range system build. Always make sure that a purchased PSU is capable of powering your system. Remember that a higher PSU capacity does not necessarily equate to a higher wattage output and a more expensive electricity bill. In fact, you may find that a higher capacity PSU will function more efficiently than a lower capacity PSU because it is dealing with a lower percentage of its maximum load - that is, it is not being stressed to the same extent.

The Rosewill CAPSTONE-550 has an 80 Plus rating of Gold. This means the PSU operates at average efficiency levels of at least 87%, 90%, and 87% for loads of 100%, 50%, and 20% respectively. Gold is the second-best 80 Plus certificate available, and as such the Rosewill CAPSTONE-550 is extremely efficient and comes highly recommended. The actual efficiencies for this PSU are 89.52%, 90.81%, and 88.82%, for loads of 100%, 50%, and 20%.

The dimensions of the Rosewill CAPSTONE-550 (LxWxH) are 16.5cm x 15cm x 8.6cm. Make sure to compare these measurements against the case you desire if planning on using it in a build.

The Rosewill CAPSTONE-550 is not modular, meaning that cables are built into the PSU itself and cannot be taken out and connected back in as necessary. This can result in difficult cable management and consequently a messy build and poor airflow.

The Rosewill CAPSTONE-550 is not designed for low volumes, meaning that its constant drone while your PC is on could potentially be noticeable and irritating, though this may only be a problem for those that require silent environments.