Crazyjeeper
NickGyver
Well, here are their comparisons
3650:
GPU: RV635
Core Clock: 725 MHz
Shader Clock: 725 MHz
Memory Clock: 800 MHz (1600 DDR)
Memory Bandwidth: 25.6 GB/sec
FLOPS: 174
Pixel Fill Rate: 2900 MPixels/sec
Texture Fill Rate: 5800 MTexels/sec
4650
GPU: RV730
Core Clock: 600 MHz
Shader Clock: 600 MHz
Memory Clock: 500 MHz (1000 DDR)
Memory Bandwidth: 16 GB/sec
FLOPS: 384
Pixel Fill Rate: 4800 MPixels/sec
Texture Fill Rate: 19200 MTexels/sec
Plus, the 3650 is GDDR3, while the 4650 is GDDR2.
That is all relative, the core is a far better design on the 4650. You don't need higher clock speeds. The pixel fill rate and texture rates are where you notice performance.