I just installed a new GEForce GTX550 TI.   This card comes with a cable that plugs into the power adapter at the back of the card.  The other end of this cable has two male connectors that plug into the standard 4 pin female computer power supply connectors.   Do both male connectors have to receive power or can one be left unconnected?
 
Thanks,
 
Ian

Lets start with the fun stuff.... Welcome to the forums!!!
 
Now for the nitty gritty.  IF you are using the power adapter, you need to connect both power connections to the adapter.  One 6 pin PCIE power connection is capable of pushing 150W and each molex connection pushed 75W, so 75 + 75 = 150.
The thing is, the power adapters are meant for temporary use for best performance.  You really want to see if your PSU has a 6 pin power connection built into it.  If it does, use that.

ian00bell

Molex connectors  - good to finally know the name of this connector.

Is is necessary to provide the GTX550 with power or can I get away without providing additional power to the GTX550? I bought the GTX550 specifically for the game Men of War - Assault Squad. 

Thanks,

Ian

 
You -must- connect the card with the proper power -period-
 
It appears that you may not have available, another 4pin molex connector to use... is that the case?
 

If you cant find another "free" molex to use, you will have to buy a "Molex Y Adapter"

 
Simply find another molex thats being used, unplug it and put in the adapter, the hook up whatever it was you unplugged and you will now have a free end to use.
*Note you must use a -different- molex than the one you already have hooked up.
 
A molex Y splitter can be found at any computer shop for about $3 

I've got a Antex 500W, 12V but only rated at 17A .   The y-splitter is a good idea and I'll go pick one up.  But it looks like I will have to upgrade to at minimum 24A PSU.    Thank you for your input.
 
 

Agreed, you probably have (2) 12v rails at 17a if its a 500w ANTEC, but I would certainly check the sticker and make sure

I have only had 1 of the 2 molex connectors in use for the past 1 and a half years on my 2 molex to 6 pin power thats connected to my gtx 550ti with no problems. I dont know if thats normal or healthy for the gpu or power supply but it works. I have overclocked and pushed the voltage to the max with afterburner, so seems that 1 molex works fine.