I am sorry I did not mentioned which card I have bought. I have bought Nvidia Geforce GT 440. I compared it with nVidia geforce GT 520 and found that Nvidia Geforce GT 440 is better. Because of these things--
nVidia GeForce GT 440 GDDR3:- nVidia GeForce GT 520
Core Clock: 810 MHz Core Clock: 810 MHz
Shader Clock: 1620 MHz Shader Clock: 1620 MHz
Memory Clock: 900 MHz (1800 DDR) Memory Clock: 900 MHz (1800 DDR)
Memory Bandwidth: 28.8 GB/sec
Memory Bandwidth: 14.4 GB/sec
FLOPS: 466.56 GFLOPS FLOPS: 77.76 GFLOPS
Pixel Fill Rate: 12960 MPixels/sec Pixel Fill Rate: 3240 MPixels/sec
Texture Fill Rate: 22680 MTexels/sec Texture Fill Rate: 6480 MTexels/sec
Memory Type: GDDR3 Memory Type: GDDR3
Memory Bus Type: 64x2 (128 bit) Memory Bus Type: 32x2 (64 bit)
DirectX Compliance: 11.0 DirectX Compliance: 11.0
OpenGL Compliance: 3.2 OpenGL Compliance: 4.1
PS/VS Version: 5.0/5.0 PS/VS Version: 5.0/5.0
Process: 40 nm Process: 40 nm
Shader Processors: 96 Shader Processors: 48
Texture Units: 28 Texture Units: 8
Raster Operators 16 Raster
Operators 4
And I am playing Crysis 2 with full settings and it is extremely smooth. I have Intel(R) Core(TM) i3 CPU 540 @ 3.07GHz with 4 GB DDR3 RAM. This card was of 3900 Rs. I guess in this range it is best. Ati hd 4670 is 500 Rs expensive and difference between these two is negligible.