Silverstone Tek Strider Series ATX12V/EPS12V 550W 80+ Gold PFC Power Supply with Full Modular Cables ST55F-G is for sale at $110 on Amazon. Would this be a good PSU for my Dell XPS 420 (Q6600 3.0 GHz) and GTX 670? I have a complement of SSD, HDD, DVD and BD drives, and the new PSU would be replacing the 5-yr old 450 W OEM PSU. I notice that all new PSU's have an off rocker switch, but my existing PSU/case does not. Will this be a problem for installation?