600/550W PSU (400W in usage) BRONZE vs. PLATINIUM

[computercpu]

Hello so as you can read from the topic I have two PSUs to choose from. All in all my components total Watt usage is 400W. The two PSU's to choose from are:

1) Rosewill Fortress 550w (80+Platinium): http://www.newegg.com/Product/Product.aspx?Item=N82E16817182082
2) Silverstone 600w strider essential (80+Bronze): http://silverstonetek.com/product.php?pid=463&area=en

So my actual question is that how many Watts would the PLATINIUM Rosewill 550W use versus the BRONZE SIlverstone 600W when my components total watt usage is 400W.

 

[Dark Lord of Tech]

Bronze and Platinum is just the efficiency rating.
http://www.hardwaresecrets.com/understanding-the-80-plus-certification/

I would get the Rosewill , but if you can get the Corsair below.

https://www.jimms.fi/fi/Product/Show/117116/cp-9020090-eu/corsair-550w-rm550x-modulaarinen-virtalahde-80-plus-gold
RMX550W.