I WANT TO BUY A PERFECT GRAPHIC CARD WHICH DONOT REQUIRED EXTRA POWER SUPPLY I HAVE INTEL I5 4670,4GB RAM,1TB HARDDISK,MOTHERBOARD INTEL DH87MC,300WATT SMPS I DONOT WANT TO CHANGE MY SMPS SO PLEASE GIVE ME ADVICE.
Get ZoTAC GTX 750 GDDR5 Or Zotac GT 730 GDDR5 Depending On Your Budget But 750 Is Highly Recommended And You Can Run Both The Cards And Both Can Run In Your PSU But You Must Check Once Whether Your PSU Has 20+ Amps On +12v Rail If So No Need To Worry...In Case You've Less Than 20 Amps Then You Can Only Run 730 And Not 750
I don't know much about SMPS power supplies, but I'm going to guess it's been made to supply enough amps across the different voltage rails as required for modern computers. You said you have 300W then later 250W, which is it? My suggestion of GPU would be either the GTX 750 or 750Ti with 2GB DDR5. Something like this one http://www.amazon.com/dp/B00IDG3IDO/ref=psdc_284822_t1_B00I6DLIB8
It does not require any extra power connections and consumes a maximum of 60W and would run on a 300W power supply just fine.
You Have A Very Low End PSU Of 250w You Can Hardly Run Any GDDR5 GPU,The Only And Only One You Can Try Is GT 730 GDDR5....And GT 610 Too But It's DDR3...
Well r7 250 1gb doesn't require additional power supply so one good solution would be that,but it will bottleneck hard with your cpu,it costs around 80 euros though so i think it's the best you can take at this price point.