KitGuru tried the Silverstone SST-SX550 550W PSU
A quote from the article:
Today we take a look at one of the latest power supplies from Silverstone ? the SST-SX550. This is an SFX power supply designed to fit inside small form factor cases. It features 80 PLUS gold certification, a single +12V rail with a substantial 45A rating and it supports dual PCI-E 6+2 pin connectors. It is also rated to deliver a constant 550 watts while operating at 50C, 24/7.Silverstone SST-SX550 550W PSU Review @ KitGuru