Yes 380w is totally fine however I have never heard of that psu before so I would be careful. I think you should be more than fine because that build won't consume anywhere near 380w on load but I'd replace the psu as soon as possible.
Hope I helped.
:)
Hey, the EVGA sc is the best 750ti however if I had to choose between the two you sent. I'd choose the MSI due to the higher clock speed at stock.
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:)
Don't bother putting it back on, just put it in the box when you send it back, providing you are within a month of purchase Amazon aren't very picky about refunds.
(I send computer components back to amazon all the time.)
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:)