EVERYONE STOP.
WAIT
SO MUCH MISINFORMATION.
HOLD THAT SHIT.
OK. Let's start.
Firstly, the 230W/250W markings on your power supply are NOT
VOLTAGE MARKINGS. The voltage markings, if any, are 110/240V
located near or on the red switch at the rear of your power supply.
230W/250W is either:
a) Nominal Load Output/Peak Load Output
OR
b) Total combined +12V power/Total combined +3.3V +5V +12V
power
Secondly, the GT520 is far too weak for any real gaming at
1080p. A HD6850 1GB DDR5 is going at clearance prices now, and is a
worthy buy bing far more powerful than the GT520. Pair that with
AMD's Catalyst 12.1 drivers (please do not use 12.4 and above) and
you'll have a pretty good combo that's capable of playing just
about any games.
For power supplies, the FSP Aurum 400 is a unit that's far more
than just capable than handling your system. It does not mean that
a PSU with higher wattage is better. Sim Lim sells $18 crap that
boasts to be able to do 680W. Do you believe that shit?
Besides, the real calculations for your system, assuming you buy
the HD6850 are as follow:
CPU: 95W
GPU: 130W
HDD: 20W
RAM+MB+Peripherals: 80W
Of course, the real world figures are far less scary than this.
These are TDP figures; and you'll only achieve them if you're
running IBT + Furmark + HDTune bench all at the same time. Of
course, no one does that, its insanely stupid to do that for
extended periods - people only do this if they want an ultimately
stable overclock.
Additionally, if you're running such a low load on a high cap PSU,
chances are that your efficiency is going to be crap. The ideal
efficiency range of a PSU falls between 40-70%. And whilst you may
argue that my calculated maximum demand of 325W is already at 80%,
I shall reiterate that it only occurs AT MAXIMUM STRESS LEVELS.
When gaming, it consumes way less than that amount of power. And I
don't believe you spend all your time gaming either. What about the
times when you're just surfing the Net? I'm sure it constitutes 70%
of your daily PC usage. That is when the correct PSU matching comes
in. Idle power draw for Sandy Bridge and AMD cards HD5000 and
onward are so ridiculously low that the total power draw falls to
30% or less.
So yes, end of story. 6850 + Aurum 400 is your best bet.