The motherboard is an Asus P4S800 and the replacement PSU will hopefully be
one of these:
http://www.ebuyer.com/UK/product/115238
I mentioned "all major components" above because it is not
only the motherboard considered when estimating the current
requirements for a system. We could guess, but still have
insufficient info to determine if that PSU is appropriate.
At least we do know the board uses 12V rail (stepped down
by the board to lower voltage) to power the CPU, so the 5V
current capability of the PSU is not so much of an issue.
That is a reasonably good PSU, will probably be sufficient
unless you have a lot of hard drives or a power hungry,
higher-end gaming video card(s).
There is very little airflow at the moment.
Don't depend on the PSU to cool the case. Improve the case
airflow sufficiently while ignoring the impact of the PSU on
case cooling.
The PSU I'm looking at has a
large fan and I'm also getting an additional fan. This may work best as a
front intake fan, if not I'll use it as an additional rear exhaust fan.
The purpose of the large fan is to produce less noise, but
if the case isn't cooled well (otherwise), the fan may
increase in RPM to compensate and no longer be so quiet.
As per AMD and Intel recommendations, a case should have a
rear exhaust fan in addition to the PSU exhaust, and a
reasonably sized intake area on the front, bottom of the
case. The rear exhaust fan should be the first fan added to
the case, then if this isn't enough, you would pay more
attention to which parts are still running too hot and go
from there planning which further fan locations will address
those parts, OR if it isn't a fan but rather a heatsink
problem. Front fans are generally used when there isnt'
enough room for a good sized fan in the rear or if the hard
drives need more airflow, due to having a lot of them or
that the case is designed such that it doesn't concentrate
enough of the passive intake air through the drive rack and
adding the fan will blow, redirect more air through the
drive rack.
