psu help please

I currently have the following pc:

amd 1.4 tb
512mb
40gb
geforce fx 5900
cdrw
dvd rom
modem
network card
firewire card
300w psu

The graphics card is ok but the rest and in particular the processor is starting to struggle a bit with the latest games so i have decided to upgrade.

I'm too lazy to build my own and i don't want to go down the mail order route as it sounds like it can be a nightmare if you get a dud and need to send it back so i have decided to purchase a branded machine form the likes of pc world or comet as it is more convienient for me even though it is not the best value.

The concern i have is that all of these pc's have psu's that range form 180-250 watts which seems really low.
I wanted to buy one of these and then replace the crappy graphics cards that come with these machines with my fx 5900 card but i am worried that
this will overload the psu and therefore will not work.


For example i have found the following acer pc Aspire T130 with the following spec :

AMD Athlon 64 3200+, Microsoft® Windows® XP Home Edition, Microsoft® Works, 160GB, 512MB DDR, DVD-RW+, GF FX5200 128MB, TVO DVI, Modem/LAN, Speakers

This only comes with a 200w psu and when i put this spec into the power supply wattage calculator link elsewhere on this forum it recommends something like a 275 watts psu ???

Also i have read that my fx 5900 uses 20 watts more that the fx 5200 so i would obviously be increasing the power requirements, do you think it would work ?

Any advice appreciated.


Cheers
Jubbly

i know its a long one, but anyone ???

200W is getting on the low side. It might just run all the things in the system but you are certainly taking a chance. The PSU is often overlooked but you should pay as much attention to it as any other component. I would not only look at the power rating but also the brand make as you also need to take in the current supplied and how strong the rails are.

As a rule of thumb I wouldn't go below 300W for the average system and stay to well known makes of good PSU i.e Sparkle (Fortran) Antec, OCZ, Enermax etc.

Most important thing when buying a PSU is not the rating, but the brand - Antec, Tagan, Thermaltake, CWT, etc. For the rating, I just went for a Tagan 480W - hopefully it'll last me a while, and is BTX compatible (if that ever sees the light of day). Right now, I'd go for at least 350W.

But whatever you do, don't try the cheap and nasty option on your PSU - there's no point buying a whole load of expensive components and having it all blown up by a cheap PSU.

And, no matter what, don't buy a Q-Tec ;)