How do i choose the right PSU?

[DOCOFDEATH]

I want to know on what basis you choose the best suitable PSU for your PC? I'll be buying Sapphire AMD/ATI HD 7750 1 GB GDDR5 Graphics Card, its written Power Supply Required- 450 W. So does the GPU need 450w(only for the GPU) or the PSU should be of 450w? I'm really confused.
So my PC specs are motherboard- ASUS P5G41-M LX
Processor- Intel pentium e5700 @3ghz
Ram-4
basic things like keyboard, mouse, webcam, modem, headphones
So which is the apt psu that will work with this system?

 

[Outlander_04]

Card makers recommend a wattage and it usually seems to be based on you choosing the worst quality psu any dodgy maker would dare put that wattage sticker on

Instead use this
http://www.realhardtechx.com/index_archivos/Page362.htm

and make sure you buy an 80+ bronze [ or better ] psu . Nothing lower is good enough

and dont buy a CM since they lie about their psu's being 80+ bronze

 

[smorizio]

with power supplys and the needed output it the 12v line that you have to look at. simple rule is take the cpu wattage and the max wattage of the gpu...say cpu is 100w then gpu is 300w. 400w/12 would be 34w. so you would look on the 12v line and make sure you had more then 34 amps on the 12v rail. most power supply you dont run near there max output you shorten there live and they run hot. alway better to oversize unit by 100w. myself I would for the money pick up a 650w unit. it be larger then you need now but if you upgrade your system in a year or two you wont have to toss the unit. also with newer power supplys make sure there haswell tested. the newer cpu run so low on low power states that the older power supply cant go that low. the newer intel cpu will be low power chips.

 

[verma1891]

No, 450W psu is required to power up a whole system (with general specs like 2 ram, 2 hdd, few fans etc). That card alone will probably suck in 100-120W. Your system may not even require 450 W. But 450W is recommended minimum to cover up all the crap psu's out there.
Invest in a higher efficiency PSU only if you keep your machine running for extended periods of time, otherwise, a good 80+ bronze is ok.
Here are some good options for your build. Choose anyone according to your budget-
http://pcpartpicker.com/part/antec-power-supply-vp450
http://pcpartpicker.com/part/corsair-power-supply-cx430m
http://pcpartpicker.com/part/corsair-power-supply-cx500
http://pcpartpicker.com/part/corsair-power-supply-cx430
http://pcpartpicker.com/part/evga-power-supply-100b10500kr

 

[DOCOFDEATH]

Then i got a question if i buy a psu thats 1000w will there be a problem for the other hardware in the pc?

 

[verma1891]

Then i got a question if i buy a psu thats 1000w will there be a problem for the other hardware in the pc?

There is no upper limit of wattage. You can put 1000W where 450W will do, you wont hurt anything except your pocket. (if the psu is not a real 1000W crap)

 

[DOCOFDEATH]

Thanks guys! much appreciated