[URGENT] Which GTX 750 is better + Is my power supply enough?

[SkyDieRay]

I have a 400W power supply.

Palit GeForce GTX 750 Ti StormX Dual 2GB DDR5 128-bit:
http://www.pcgarage.ro/placi-video/palit/geforce-gtx-750-ti-stormx-dual-2gb-ddr5-128-bit/

GIGABYTE GeForce GTX 750 Ti OC2 WindForce 2X 2GB DDR5 128-bit:
http://www.pcgarage.ro/placi-video/gigabyte/geforce-gtx-750-ti-oc-windforce-2x-2gb-ddr5-128-bit-1/

ONLY IF I need a new power supply, is this ok? http://www.pcgarage.ro/surse/segotep/atx-500wh/

EDIT: I have this atm http://www.amazon.co.uk/PSU-400W-Chieftec-APS-400S-A-135/dp/B001J4RZYA

 

[bradley4jacks]

could you find your current parts on here: https://uk.pcpartpicker.com/parts/partlist/
Just so i can see the current power consumption.
And I would say the Palit Card looks slightly better

 

[SkyDieRay]

could you find your current parts on here: https://uk.pcpartpicker.com/parts/partlist/
Just so i can see the current power consumption.
And I would say the Palit Card looks slightly better

i7-2600 @3.4GHz
asrock h61icafe
2x4GB DDR3-1333
GTS 450

EDIT: I already had this from another thread

 

[bradley4jacks]

could you find your current parts on here: https://uk.pcpartpicker.com/parts/partlist/
Just so i can see the current power consumption.
And I would say the Palit Card looks slightly better

i7-2600 @3.4GHz
asrock h61icafe
2x4GB DDR3-1333
GTS 450

EDIT: I already had this from another thread

from the spec's you've given me, I would say the power consumption of your rig with a GTX 750Ti in it would be about 250W so I would say that your 400W psu should be more than enough, although this is only an estimate but I can't imagine it being out by 150W .

http://uk.pcpartpicker.com/p/r6mb3C
(I added a generic 1TB hard drive just to get as good an estimate as possible, and the memory is faster to have a bit of an over estimate)