Will my power supply work with my other parts?

[Zerolimitz]

Ok

this are the parts

Asus mother board - Newegg.com - ASUS M5A99X EVO AM3+ AMD 990X SATA 6Gb/s USB 3.0 ATX AMD Motherboard with UEFI BIOS
AMD Processor - Newegg.com - AMD Phenom II X4 970 Black Edition Deneb 3.5GHz 4 x 512KB L2 Cache 6MB L3 Cache Socket AM3 125W Quad-Core Desktop Processor HDZ970FBGMBOX
Corsair Memory - Newegg.com - CORSAIR Vengeance 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model CMZ8GX3M2A1600C9B
HD 6870 Video Card - Newegg.com - XFX HD-687A-ZHFC Radeon HD 6870 1GB 256-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card
Power Supply - Newegg.com - XFX Core Edition PRO550W (P1-550S-XXB9) 550W ATX12V 2.2 & ESP12V 2.91 SLI Ready CrossFire Ready 80 PLUS BRONZE Certified Active PFC Power Supply
Anyone know how to know how many watts do you need for yours computer parts?

 

[Roark]

Video cards usually indicate how many watts your system will need overall.
I check 1 of 3 (or all 3) places, either the Newegg Details tab of the card, the AMD/Nvidia website, or guru3d.com.

500 Watt or greater power supply with two 75W 6-pin PCI Express® power connectors recommended

So a 550W power supply should work just fine for your build.

On a side note, have you taken a look at the AMD FX-4100 CPU?
Its cheaper than the 970 with the power of a 980 from what I've seen, and will work with your build without any changes.