How to know what power supply you need

[techguy123]

Hello,
i am building my first computer and i don't know which power supply i need can you help? me these are my specs:

-Intel Core i5-3570K Ivy Bridge 3.4GHz (3.8GHz Turbo) LGA 1155 77W Quad-Core Desktop Processor Intel HD Graphics 4000

-radeon hd 7850 sapphire oc edition

-16gb ddr3 ram memory

-ASRock B75 PRO3 LGA 1155 Intel B75 HDMI SATA 6Gb/s USB 3.0 ATX Intel Motherboard

-Western Digital Caviar Green WD10EZRX 1TB IntelliPower SATA 6.0Gb/s 3.5" Internal Hard Drive -Bare Drive

-ASUS Black Blu-ray Drive SATA Model BC-12B1ST/BLK/B/AS - OEM

-windows 7 home premium 64-bit OEM

 

[Outlander_04]

Graphics cards are the main power user in a computer so its safe to size your psu using this
http://www.realhardtechx.com/index_archivos/Page362.htm

Buy only 80+ bronze [ or better] rated units . Check that it has the power connectors you need . Esp pci-e power connectors for graphics cards

And you dont even need 8 gig of RAM for a gaming computer

 

[Ironslice]

First of all:
Get only 8GB of RAM
Get this motherboard: http://www.newegg.com/Product/Product.aspx?Item=N82E16813157293
Get this power supply: http://www.newegg.com/Product/Product.aspx?Item=N82E16817139020

 

[meow_way]

Due to the graphics card you need a 500w cpu; however, I'd hedge my bets esp for further additions with a 650w one.

 

[techguy123]

Thanks dude

 

[techguy123]

Best answer selected by techguy123.

 

[techguy123]

Hey Ironslice with this i can run a gtx 570 or i should stay with my radeon hd 7850?