But isnt a higher clock speed and higher shader and mem speed indicative of better performance? Also why does 550v only support Directx 10.1 and Sharder mode 4
But yeah I saw that the 4650 has better performance that 5470 in the link you provided...
No,there are many other important factors than clock speed, for example 550v has 320 unified pipelines compared to 80 on 5470M,therefore its much faster.
And the reason that it supports DX 10.1 and SM4 is because its based on HD 4xxx architectures(which support DX 10.1 and SM4)
5470 is better...is uses dx11 which means it will last longer than 550v....number of transistors and stream processing units depends upon the technology which company has used. eg: geforce technology uses less stream processors but is somewhat higher in clocks....similarly radeon technology uses some more stream processing units but compromises in some other clocks........although performance remains equal.
5470 has DX11 and more new features but it doesn't come close to 550v's performance,because like i mentioned,550v has much more stream processors therefore it performs better in games.
Check some benchmarks from notebookcheck.net and you'll see how large the performance gap is between them.
Performance wise the 550v is obviously better, but the 5470 will best the 550v in terms of power draw for being lower-performance and newer.
The reason the 550v only supports DX10 is because it is a older chip based of the HD4000 with a new name while the 5470 is a "real" 40nm HD5000 part. But for chips this level, DX11 shouldn't matter at all, after all even a 5870M struggles with DX11 effects.