How many watt psu i really need?

[Arch77]

Hello everyone,i need your help on how many watt i really need with my system.
recently ,it came at my hands an msi gtx 750ti and i wondering about psu,,i know this card needs 400w based on msi guide.
my system is:
motherboard: microatx gigabyte HA65M-D2H-B3
cpu : intel i5 2400 3.10 ghz 1155 socket sandy bridge
ram : corsair ddr3 2x2 gb (4)gb 1333mhz
hdd : 2 sata hdd 3.5'' 7200 rpm
fans : cpu fan default, 1x80mm,2x120mm
optical drive: 1 dvd/cdrw
in use all the time almost 3 usb.
now i have a 600w psu and i wanted to change it with some 80 plus efficiency with a quality one 500w.
i must say that idon't use or i will,, sli or crossfire and mostly i'm playing at mid and high graphics,i'm not chasing ultra high graphics generally.
i run calculator test in http://www.extreme.outervision.com and some others and almost all gave results at 343 watt recommended psu.
so how come this card needs 400w psu and same time tests says 343?
i know though,that i will need some more in case of overclocking card in some games,,so a 500w quality psu it will be ok or should i go with 450w ? or with 450 will be at limits?
thanks in advance anyone that can help a little because at stores many says take one with many watts as possible and you will be ok.
why someone will take one big psu if will not need actually one? based on my components i think i will be ok with a good one 500w 80 plus bronze.
thanks

 

[Sammyjo20]

Hello everyone,i need your help on how many watt i really need with my system.
recently ,it came at my hands an msi gtx 750ti and i wondering about psu,,i know this card needs 400w based on msi guide.
my system is:
motherboard: microatx gigabyte HA65M-D2H-B3
cpu : intel i5 2400 3.10 ghz 1155 socket sandy bridge
ram : corsair ddr3 2x2 gb (4)gb 1333mhz
hdd : 2 sata hdd 3.5'' 7200 rpm
fans : cpu fan default, 1x80mm,2x120mm
optical drive: 1 dvd/cdrw
in use all the time almost 3 usb.
now i have a 600w psu and i wanted to change it with some 80 plus efficiency with a quality one 500w.
i must say that idon't use or i will,, sli or crossfire and mostly i'm playing at mid and high graphics,i'm not chasing ultra high graphics generally.
i run calculator test in http://www.extreme.outervision.com and some others and almost all gave results at 343 watt recommended psu.
so how come this card needs 400w psu and same time tests says 343?
i know though,that i will need some more in case of overclocking card in some games,,so a 500w quality psu it will be ok or should i go with 450w ? or with 450 will be at limits?
thanks in advance anyone that can help a little because at stores many says take one with many watts as possible and you will be ok.
why someone will take one big psu if will not need actually one? based on my components i think i will be ok with a good one 500w 80 plus bronze.
thanks

I would go for the 500 watt one bare minimum. 450 is really cutting it close as you said, your GPU uses 400.
Hope this helps
- Sam

 

[Computer Blackwidow]

Check your power usage here:
http://powersupplycalculator.net/
If it is less than 400w(less than 350w recommended) then you can go with 500w. But get a good PSU because PSUs are the most important thing in the computer. I will recommend the EVGA, Seasonic or XFX as they are the best manufacturers of PSUs. 50+ bronze will be good. Best Luck.
CB

 

[Arch77]

Thanks,both of you guys,i think too i will stick with a 500w psu based on my components dor the moment.
i had on my mind a CORSAIR CX500 - 80 PLUS BRONZE but i will check also the others blackwidow said and purchase best on category.or i can keep my 600w i already have and go for gigabyte gtx 760 , insteed of msi gtx 750 ti already given to me but i think for now gtx 750 ti it's still pretty good one for plenty of games on mid-high graphics and some case on ultra settings.although i never played at 1920x1080 ,so for my demands i will be ok. thanks again for your answers,were really helpful