450W does not mean that output will be also same.
CM600 works on almost 70% efficiency and VX450 works at 85% efficiency, fthese are from the data sheet of the PSU.
CM600 = 420W real output and VX450 = 382W real output, on max loads, that is wha nish means
yea..almost
check this too-
*www.atomicmpc.com.au/forums.asp?s=2&c=7&t=9354
and quote from hardware secrets-
You will bring home a relatively inexpensive power supply that even though is sold as being a 450 W unit can deliver up to 570 W at 48º C – in fact Corsair could have easily labeled this power supply as a 500 W unit, but they preferred to stay on the safe side.
also it has that 8pin cpu power connector which the CM Extreme 600 lacks