does gtx 750ti work on 290watt ? then i have i3 4150 3.50 Ghz and 4 GB ram !

Solution
Assuming your machine is a dell optiplex or similar and that pau is one of dells proprietary units with an 8 pin motherboard connector you'll get away with a bus powered 750ti fine

A PSU upgrade is out of the question anyway , these units only supply 12v current & the 3.3/5v split is done by the board.
The bonus of this (if you can call it that) is that you have 260-270 12v wattage available for what is realistically only a 200w system even with a 750ti installed.
Of course, the factory overclocked ones with multiple fans will need a 6 pin. I was referring to the 750 Tis' at stock speeds. Most don't need one, like my Asus. I guess Gigabyte is an exception.

I suppose your Dell PSU should be fine. Was yours an old Optiplex?

EDIT: OP, just make sure the 750Ti you're getting doesn't need a 6 pin, like maxalge said.
 
Assuming your machine is a dell optiplex or similar and that pau is one of dells proprietary units with an 8 pin motherboard connector you'll get away with a bus powered 750ti fine

A PSU upgrade is out of the question anyway , these units only supply 12v current & the 3.3/5v split is done by the board.
The bonus of this (if you can call it that) is that you have 260-270 12v wattage available for what is realistically only a 200w system even with a 750ti installed.
 
Solution