How many Watts of power does my PSU need

[Computer tec]

How many W of power does my PSU need to have to run this build.

Thinking of getting a seasonic X, or a seasonic Platinum PSU
Just don't know how many Watts of power i need.
PC Build Spec

CPU- i7-3970x
GPU- GeForce GTX 690
SSD – Intel 520 120GB Sata3
MOBO- Asus Rampage IV Extreme
CASE – Cosmos II
RAM – Mushkin Readline Ridgeback 4*4 = 16GB
DVD- Asus BD Drive – BC-12B1ST
Sound Card – ROG Xonar Phoebus


Water Cool Spec
CPU Block – EK Supremacy – Acetal + Nickel
GPU Back Plate – EK FC7970 Back Plate – Black CSQ
GPU Block – EK-FC7970 Acetal + Nickel CSQ
Pump – Laing D5 Vario 12V Pump Motor
Pump Top – EK-D5 X Top CSQ-Acetal
Radiator – EK-Cool Stream RAD XT (480)
Reservoir – EK – RES 3 250
Fans 120mm – Scythe Gentle Typhoon AP-15 1850rpm Fans *4
Tube – Primochill Pro LRT Black 3m
Fittings *10 EK – PSC 10mm – G1/4 Black

 

[popatim]

are you planning on overclocking? 1000w to 1200w
if not an 850w should be good.

My reasoning:
cpu - 130w
Mobo 125w
GPU - 400w
Case (w/fans) 50w
drives - 15w
pump - 25w? (i think thats about right)
--------------------------
total = 745w max at all stock setting.