Hi. Will a 450W MS-TECH( pretty much no name) psu handle a HD 6670 considering that HD6670 consumes only 55w? Btw the max power on v12 rail is 300w and 12v1-17A and 12V2-17A. Currently I have a dell optiplex 380 (e5800 3.2ghz dual core 2gb ddr3 1xsata hdd 80GB). Do I really need a top brand? Thanks in advance.